Apache Tomcat^®

• Apache Tomcat 9.x vulnerabilities
• Fixed in Apache Tomcat 9.0.10
• Fixed in Apache Tomcat 9.0.9
• Fixed in Apache Tomcat 9.0.8
• Fixed in Apache Tomcat 9.0.5
• Fixed in Apache Tomcat 9.0.2
• Fixed in Apache Tomcat 9.0.1
• Fixed in Apache Tomcat 9.0.0.M22
• Fixed in Apache Tomcat 9.0.0.M21
• Fixed in Apache Tomcat 9.0.0.M19
• Fixed in Apache Tomcat 9.0.0.M18
• Fixed in Apache Tomcat 9.0.0.M17
• Fixed in Apache Tomcat 9.0.0.M15
• Fixed in Apache Tomcat 9.0.0.M13
• Fixed in Apache Tomcat 9.0.0.M10
• Fixed in Apache Tomcat 9.0.0.M8
• Fixed in Apache Tomcat 9.0.0.M3

This page lists all security vulnerabilities fixed in released versions of Apache Tomcat 9.x. Each vulnerability is given a security impact rating by the Apache Tomcat security team — please note that this rating may vary from platform to platform. We also list the versions of Apache Tomcat the flaw is known to affect, and where a flaw has not been verified list the version with a question mark.

Note: Vulnerabilities that are not Tomcat vulnerabilities but have either been incorrectly reported against Tomcat or where Tomcat provides a workaround are listed at the end of this page.

Please note that binary patches are never provided. If you need to apply a source code patch, use the building instructions for the Apache Tomcat version that you are using. For Tomcat 9.0 those are building.html and BUILDING.txt. Both files can be found in the webapps/docs subdirectory of a binary distribution. You may also want to review the Security Considerations page in the documentation.

If you need help on building or configuring Tomcat or other help on following the instructions to mitigate the known vulnerabilities listed here, please send your questions to the public Tomcat Users mailing list

If you have encountered an unlisted security vulnerability or other unexpected behaviour that has security impact, or if the descriptions here are incomplete, please report them privately to the Tomcat Security Team. Thank you.

Low: host name verification missing in WebSocket client CVE-2018-8034

The host name verification when using TLS with the WebSocket client was missing. It is now enabled by default.

This was fixed in revision 1833757.

This issue was reported publicly on 11 June 2018 and formally announced as a vulnerability on 22 July 2018.

Affects: 9.0.0.M1 to 9.0.9

Important: Information Disclosure CVE-2018-8037

If an async request was completed by the application at the same time as the container triggered the async timeout, a race condition existed that could result in a user seeing a response intended for a different user. An additional issue was present in the NIO and NIO2 connectors that did not correctly track the closure of the connection when an async request was completed by the application and timed out by the container at the same time. This could also result in a user seeing a response intended for another user.

This was fixed in revisions 1833825, 1833831, 1837530 and 1833906.

This issue was reported to the Apache Tomcat Security Team by Dmitry Treskunov on 16 June 2018 and made public on 22 July 2018.

Affects: 9.0.0.M9 to 9.0.9

Low: CORS filter has insecure defaults CVE-2018-8014

The defaults settings for the CORS filter are insecure and enable supportsCredentials for all origins. It is expected that users of the CORS filter will have configured it appropriately for their environment rather than using it in the default configuration. Therefore, it is expected that most users will not be impacted by this issue.

This was fixed in revision 1831726.

This issue was reported publicly on 1 May 2018 and formally announced as a vulnerability on 16 May 2018.

Important: A bug in the UTF-8 decoder can lead to DoS CVE-2018-1336

An improper handing of overflow in the UTF-8 decoder with supplementary characters can lead to an infinite loop in the decoder causing a Denial of Service.

This was fixed in revision 1830373.

This issue was reported publicly on 6 April 2018 and formally announced as a vulnerability on 22 July 2018.

Affects: 9.0.0.M1 to 9.0.7

Important: Security constraint annotations applied too late CVE-2018-1305

Security constraints defined by annotations of Servlets were only applied once a Servlet had been loaded. Because security constraints defined in this way apply to the URL pattern and any URLs below that point, it was possible - depending on the order Servlets were loaded - for some security constraints not to be applied. This could have exposed resources to users who were not authorised to access them.

This was fixed in revisions 1823310 and 1824323.

This issue was identified by the Apache Tomcat Security on 1 February 2018 and made public on 23 February 2018.

Affects: 9.0.0.M1 to 9.0.4

Important: Security constraints mapped to context root are ignored CVE-2018-1304

The URL pattern of "" (the empty string) which exactly maps to the context root was not correctly handled when used as part of a security constraint definition. This caused the constraint to be ignored. It was, therefore, possible for unauthorised users to gain access to web application resources that should have been protected. Only security constraints with a URL pattern of the empty string were affected.

This was fixed in revision 1823306.

This issue was reported publicly as 62067 on 31 January 2018 and the security implications identified by the Apache Tomcat Security Team the same day. It was made public on 23 February 2018.

Affects: 9.0.0.M1 to 9.0.4

Low: Incorrectly documented CGI search algorithm CVE-2017-15706

As part of the fix for bug 61201, the description of the search algorithm used by the CGI Servlet to identify which script to execute was updated. The update was not correct. As a result, some scripts may have failed to execute as expected and other scripts may have been executed unexpectedly. Note that the behaviour of the CGI servlet has remained unchanged in this regard. It is only the documentation of the behaviour that was wrong and has been corrected.

This was fixed in revision 1814825.

This issue was reported to the Apache Tomcat Security Team by Jan Michael Greiner on 17 September 2017 and made public on 31 January 2018.

Affects: 9.0.0.M22 to 9.0.1

Important: Remote Code Execution CVE-2017-12617

When running with HTTP PUTs enabled (e.g. via setting the readonly initialisation parameter of the Default servlet to false) it was possible to upload a JSP file to the server via a specially crafted request. This JSP could then be requested and any code it contained would be executed by the server.

This was fixed in revisions 1809669, 1809674, 1809684 and 1809711.

This issue was first reported publicly followed by multiple reports to the Apache Tomcat Security Team on 20 September 2017.

Affects: 9.0.0.M1 to 9.0.0

Important: Security Constraint Bypass CVE-2017-7675

The HTTP/2 implementation bypassed a number of security checks that prevented directory traversal attacks. It was therefore possible to bypass security constraints using an specially crafted URL.

This was fixed in revision 1796090.

The issue was originally reported as a failure to process URL path parameters in bug 61120 on 24 May 2017. The full implications of this issue were identified by the Tomcat Security Team the same day. This issue was made public on 10 August 2017.

Affects: 9.0.0.M1 to 9.0.0.M21

Moderate: Cache Poisoning CVE-2017-7674

The CORS Filter did not add an HTTP Vary header indicating that the response varies depending on Origin. This permitted client and server side cache poisoning in some circumstances.

This was fixed in revision 1795813.

The issue was reported as bug 61101 on 16 May 2017. The full implications of this issue were identified by the Tomcat Security Team the same day. This issue was made public on 10 August 2017.

Affects: 9.0.0.M1 to 9.0.0.M21

Important: Security Constraint Bypass CVE-2017-5664

The error page mechanism of the Java Servlet Specification requires that, when an error occurs and an error page is configured for the error that occurred, the original request and response are forwarded to the error page. This means that the request is presented to the error page with the original HTTP method.

If the error page is a static file, expected behaviour is to serve content of the file as if processing a GET request, regardless of the actual HTTP method. Tomcat's Default Servlet did not do this. Depending on the original request this could lead to unexpected and undesirable results for static error pages including, if the DefaultServlet is configured to permit writes, the replacement or removal of the custom error page.

Notes for other user provided error pages:

• Unless explicitly coded otherwise, JSPs ignore the HTTP method. JSPs used as error pages must ensure that they handle any error dispatch as a GET request, regardless of the actual method.
• By default, the response generated by a Servlet does depend on the HTTP method. Custom Servlets used as error pages must ensure that they handle any error dispatch as a GET request, regardless of the actual method.

This was fixed in revisions 1793468 and 1793487.

This issue was reported responsibly to the Apache Tomcat Security Team by Aniket Nandkishor Kulkarni from Tata Consultancy Services Ltd, Mumbai, India as a vulnerability that allowed the restrictions on OPTIONS and TRACE requests to be bypassed on 21 April 2017. The full implications of this issue were identified by the Tomcat Security Team on 24 April 2017. This issue was made public on 6 June 2017.

Affects: 9.0.0.M1 to 9.0.0.M20

Important: Information Disclosure CVE-2017-5651

The refactoring of the HTTP connectors for 8.5.x onwards, introduced a regression in the send file processing. If the send file processing completed quickly, it was possible for the Processor to be added to the processor cache twice. This could result in the same Processor being used for multiple requests which in turn could lead to unexpected errors and/or response mix-up.

This was fixed in revision 1788544.

This issue was identified by the Apache Tomcat Security Team on 24 March 2017 and made public on 10 April 2017.

Affects: 9.0.0.M1 to 9.0.0.M18

Important: Denial of Service CVE-2017-5650

The handling of an HTTP/2 GOAWAY frame for a connection did not close streams associated with that connection that were currently waiting for a WINDOW_UPDATE before allowing the application to write more data. These waiting streams each consumed a thread. A malicious client could therefore construct a series of HTTP/2 requests that would consume all available processing threads.

This was fixed in revision 1788460.

This issue was reported to the Apache Tomcat Security Team by Chun Han Hsiao on 11 March 2017 and made public on 10 April 2017.

Affects: 9.0.0.M1 to 9.0.0.M18

Important: Information Disclosure CVE-2017-5647

A bug in the handling of the pipelined requests when send file was used resulted in the pipelined request being lost when send file processing of the previous request completed. This could result in responses appearing to be sent for the wrong request. For example, a user agent that sent requests A, B and C could see the correct response for request A, the response for request C for request B and no response for request C.

This was fixed in revision 1788890.

This issue was identified by the Apache Tomcat Security Team on 20 March 2017 and made public on 10 April 2017.

Affects: 9.0.0.M1 to 9.0.0.M18

Low: Information Disclosure CVE-2017-5648

While investigating bug 60718, it was noticed that some calls to application listeners did not use the appropriate facade object. When running an untrusted application under a SecurityManager, it was therefore possible for that untrusted application to retain a reference to the request or response object and thereby access and/or modify information associated with another web application.

This was fixed in revision 1785774.

This issue was identified by the Apache Tomcat Security Team on 20 March 2017 and made public on 10 April 2017.

Affects: 9.0.0.M1 to 9.0.0.M17

Note: The issue below was fixed in Apache Tomcat 9.0.0.M16 but the release vote for the 9.0.0.M16 release candidate did not pass. Therefore, although users must download 9.0.0.M17 to obtain a version that includes the fix for this issue, version 9.0.0.M16 is not included in the list of affected versions.

Moderate: Information Disclosure CVE-2016-8747

The refactoring to make wider use of ByteBuffer introduced a regression that could cause information to leak between requests on the same connection. When running behind a reverse proxy, this could result in information leakage between users. All HTTP connector variants are affected but HTTP/2 and AJP are not affected.

This was fixed in revision 1774161.

This issue was identified by the Apache Tomcat Security Team on 14 December 2016 and made public on 13 March 2017.

Affects: 9.0.0.M11 to 9.0.0.M15

Note: The issue below was fixed in Apache Tomcat 9.0.0.M14 but the release vote for the 9.0.0.M14 release candidate did not pass. Therefore, although users must download 9.0.0.M15 to obtain a version that includes the fix for this issue, version 9.0.0.M14 is not included in the list of affected versions.

Important: Information Disclosure CVE-2016-8745

A bug in the error handling of the send file code for the NIO HTTP connector resulted in the current Processor object being added to the Processor cache multiple times. This in turn meant that the same Processor could be used for concurrent requests. Sharing a Processor can result in information leakage between requests including, but not limited to, session ID and the response body.

This was fixed in revision 1771853.

This issue was identified by the Apache Tomcat Security Team on 8 December 2016 and made public on 12 December 2016.

Affects: 9.0.0.M1 to 9.0.0.M13

Note: The issues below were fixed in Apache Tomcat 9.0.0.M12 but the release vote for the 9.0.0.M12 release candidate did not pass. Therefore, although users must download 9.0.0.M13 to obtain a version that includes fixes for these issues, version 9.0.0.M12 is not included in the list of affected versions.

Important: Remote Code Execution CVE-2016-8735

The JmxRemoteLifecycleListener was not updated to take account of Oracle's fix for CVE-2016-3427. Therefore, Tomcat installations using this listener remained vulnerable to a similar remote code execution vulnerability. This issue has been rated as important rather than critical due to the small number of installations using this listener and that it would be highly unusual for the JMX ports to be accessible to an attacker even when the listener is used.

This was fixed in revision 1767644.

This issue was reported to the Apache Tomcat Security Team on 19 October 2016 and made public on 22 November 2016.

Affects: 9.0.0.M1 to 9.0.0.M11

Important: Denial of Service CVE-2016-6817

The HTTP/2 header parser entered an infinite loop if a header was received that was larger than the available buffer. This made a denial of service attack possible.

This was fixed in revision 1765794.

This issue was reported as 60232 on 10 October 2016 and the security implications identified by the Apache Tomcat Security Team on the same day. It was made public on 22 November 2016.

Affects: 9.0.0.M1 to 9.0.0.M11

Important: Information Disclosure CVE-2016-6816

The code that parsed the HTTP request line permitted invalid characters. This could be exploited, in conjunction with a proxy that also permitted the invalid characters but with a different interpretation, to inject data into the HTTP response. By manipulating the HTTP response the attacker could poison a web-cache, perform an XSS attack and/or obtain sensitive information from requests other then their own.

This was fixed in revision 1767641.

This issue was reported to the Apache Tomcat Security Team on 11 October 2016 and made public on 22 November 2016.

Affects: 9.0.0.M1 to 9.0.0.M11

Low: Unrestricted Access to Global Resources CVE-2016-6797

The ResourceLinkFactory did not limit web application access to global JNDI resources to those resources explicitly linked to the web application. Therefore, it was possible for a web application to access any global JNDI resource whether an explicit ResourceLink had been configured or not.

This was fixed in revision 1757271.

This issue was identified by the Apache Tomcat Security Team on 18 January 2016 and made public on 27 October 2016.

Affects: 9.0.0.M1 to 9.0.0.M9

Low: Security Manager Bypass CVE-2016-6796

A malicious web application was able to bypass a configured SecurityManager via manipulation of the configuration parameters for the JSP Servlet.

This was fixed in revisions 1758487 and 1763232.

This issue was identified by the Apache Tomcat Security Team on 27 December 2015 and made public on 27 October 2016.

Affects: 9.0.0.M1 to 9.0.0.M9

Low: System Property Disclosure CVE-2016-6794

When a SecurityManager is configured, a web application's ability to read system properties should be controlled by the SecurityManager. Tomcat's system property replacement feature for configuration files could be used by a malicious web application to bypass the SecurityManager and read system properties that should not be visible.

This was fixed in revision 1754445.

This issue was identified by the Apache Tomcat Security Team on 27 December 2015 and made public on 27 October 2016.

Affects: 9.0.0.M1 to 9.0.0.M9

Low: Security Manager Bypass CVE-2016-5018

A malicious web application was able to bypass a configured SecurityManager via a Tomcat utility method that was accessible to web applications.

This was fixed in revisions 1754714 and 1760300.

This issue was discovered by Alvaro Munoz and Alexander Mirosh of the HP Enterprise Security Team and reported to the Apache Tomcat Security Team on 5 July 2016. It was made public on 27 October 2016.

Affects: 9.0.0.M1 to 9.0.0.M9

Low: Timing Attack CVE-2016-0762

The Realm implementations did not process the supplied password if the supplied user name did not exist. This made a timing attack possible to determine valid user names. Note that the default configuration includes the LockOutRealm which makes exploitation of this vulnerability harder.

This was fixed in revision 1758499.

This issue was identified by the Apache Tomcat Security Team on 1 January 2016 and made public on 27 October 2016.

Affects: 9.0.0.M1 to 9.0.0.M9

Note: The issue below was fixed in Apache Tomcat 9.0.0.M7 but the release vote for the 9.0.0.M7 release candidate did not pass. Therefore, although users must download 9.0.0.M8 to obtain a version that includes fixes for these issues, version 9.0.0.M7 is not included in the list of affected versions.

Moderate: Denial of Service CVE-2016-3092

Apache Tomcat uses a package renamed copy of Apache Commons FileUpload to implement the file upload requirements of the Servlet specification. A denial of service vulnerability was identified in Commons FileUpload that occurred when the length of the multipart boundary was just below the size of the buffer (4096 bytes) used to read the uploaded file. This caused the file upload process to take several orders of magnitude longer than if the boundary was the typical tens of bytes long.

This was fixed in revision 1743700.

This issue was identified by the TERASOLUNA Framework Development Team and reported to the Apache Commons team via JPCERT on 9 May 2016. It was made public on 21 June 2016.

Affects: 9.0.0.M1 to 9.0.0.M6

Moderate: Security Manager bypass CVE-2016-0763

This issue only affects users running untrusted web applications under a security manager.

ResourceLinkFactory.setGlobalContext() is a public method and was accessible to web applications even when running under a security manager. This allowed a malicious web application to inject a malicious global context that could in turn be used to disrupt other web applications and/or read and write data owned by other web applications.

This was fixed in revision 1725926.

This issue was identified by the Tomcat security team on 18 January 2016 and made public on 22 February 2016.

Affects: 9.0.0.M1 to 9.0.0.M2

Note: The issues below were fixed in Apache Tomcat 9.0.0.M2 but the release vote for the 9.0.0.M2 release candidate did not pass. Therefore, although users must download 9.0.0.M3 to obtain a version that includes fixes for these issues, version 9.0.0.M2 is not included in the list of affected versions.

Low: Directory disclosure CVE-2015-5345

When accessing a directory protected by a security constraint with a URL that did not end in a slash, Tomcat would redirect to the URL with the trailing slash thereby confirming the presence of the directory before processing the security constraint. It was therefore possible for a user to determine if a directory existed or not, even if the user was not permitted to view the directory. The issue also occurred at the root of a web application in which case the presence of the web application was confirmed, even if a user did not have access.

The solution was to implement the redirect in the DefaultServlet so that any security constraints and/or security enforcing Filters were processed before the redirect. The Tomcat team recognised that moving the redirect could cause regressions so two new Context configuration options (mapperContextRootRedirectEnabled and mapperDirectoryRedirectEnabled) were introduced. The initial default was false for both since this was more secure. However, due to regressions such as Bug 58765 the default for mapperContextRootRedirectEnabled was later changed to true since it was viewed that the regression was more serious than the security risk of associated with being able to determine if a web application was deployed at a given path.

This was fixed in revisions 1715206, 1716882 and 1716894.

This issue was identified by Mark Koek of QCSec on 12 October 2015 and made public on 22 February 2016.

Affects: 9.0.0.M1

Low: Session Fixation CVE-2015-5346

When recycling the Request object to use for a new request, the requestedSessionSSL field was not recycled. This meant that a session ID provided in the next request to be processed using the recycled Request object could be used when it should not have been. This gave the client the ability to control the session ID. In theory, this could have been used as part of a session fixation attack but it would have been hard to achieve as the attacker would not have been able to force the victim to use the 'correct' Request object. It was also necessary for at least one web application to be configured to use the SSL session ID as the HTTP session ID. This is not a common configuration.

This was fixed in revisions 1713184 and 1723414.

This issue was identified by the Tomcat security team on 22 June 2014 and made public on 22 February 2016.

Affects: 9.0.0.M1

Moderate: CSRF token leak CVE-2015-5351

The index page of the Manager and Host Manager applications included a valid CSRF token when issuing a redirect as a result of an unauthenticated request to the root of the web application. If an attacker had access to the Manager or Host Manager applications (typically these applications are only accessible to internal users, not exposed to the Internet), this token could then be used by the attacker to construct a CSRF attack.

This was fixed in revisions 1720652 and 1720655.

This issue was identified by the Tomcat security team on 8 December 2015 and made public on 22 February 2016.

Affects: 9.0.0.M1

Low: Security Manager bypass CVE-2016-0706

This issue only affects users running untrusted web applications under a security manager.

The internal StatusManagerServlet could be loaded by a malicious web application when a security manager was configured. This servlet could then provide the malicious web application with a list of all deployed applications and a list of the HTTP request lines for all requests currently being processed. This could have exposed sensitive information from other web applications, such as session IDs, to the web application.

This was fixed in revision 1722799.

This issue was identified by the Tomcat security team on 27 December 2015 and made public on 22 February 2016.

Affects: 9.0.0.M1

Moderate: Security Manager bypass CVE-2016-0714

This issue only affects users running untrusted web applications under a security manager.

Tomcat provides several session persistence mechanisms. The StandardManager persists session over a restart. The PersistentManager is able to persist sessions to files, a database or a custom Store. The cluster implementation persists sessions to one or more additional nodes in the cluster. All of these mechanisms could be exploited to bypass a security manager. Session persistence is performed by Tomcat code with the permissions assigned to Tomcat internal code. By placing a carefully crafted object into a session, a malicious web application could trigger the execution of arbitrary code.

This was fixed in revisions 1725263 and 1725914.

This issue was identified by the Tomcat security team on 12 November 2015 and made public on 22 February 2016.

Affects: 9.0.0.M1