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Ubuntu 16.04 LTS Tomcat Critical Auth Bypass Issues USN-8383-1

ubuntu
Calendar Grey June 5, 2026
Dist Ubuntu Esm H88
Several security issues in Tomcat found in Ubuntu 14.04 and 16.04 require immediate attention to maintain system integrity.
Several security issues were fixed in Tomcat.

Summary

Several security issues were fixed in Tomcat.

Software Description:

- tomcat7: Servlet and JSP engine

- tomcat6: Servlet and JSP engine

Details:

It was discovered that Tomcat incorrectly handled digest

authentication. A remote attacker could possibly use this issue to

bypass authentication restrictions. (CVE-2026-43512)

It was discovered that Tomcat incorrectly handled case sensitivity

in LockOutRealm. A remote attacker could possibly use this issue to

bypass account lockout protections and obtain sensitive information.

(CVE-2026-43513)

It was discovered that Tomcat incorrectly handled authorization when

multiple method constraints defined the same HTTP method. A remote

attacker could possibly use this issue to bypass authorization

restrictions. (CVE-2026-43515)

Topics%20covered

Topics Covered

security advisory critical Ubuntu authentication authorization sensitivity

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.04 LTS
  libtomcat7-java                 7.0.68-1ubuntu0.4+esm4
                                  Available with Ubuntu Pro
  tomcat7                         7.0.68-1ubuntu0.4+esm4
                                  Available with Ubuntu Pro

Ubuntu 14.04 LTS
  libtomcat6-java                 6.0.39-1ubuntu0.1+esm3
                                  Available with Ubuntu Pro
  libtomcat7-java                 7.0.52-1ubuntu0.16+esm2
                                  Available with Ubuntu Pro
  tomcat6                         6.0.39-1ubuntu0.1+esm3
                                  Available with Ubuntu Pro
  tomcat7                         7.0.52-1ubuntu0.16+esm2
                                  Available with Ubuntu Pro

After a standard system update you need to restart Tomcat to make
all the necessary changes.

References

https://ubuntu.com/security/notices/USN-8383-1

CVE-2026-43512, CVE-2026-43513, CVE-2026-43515

Severity
critical
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8383-1

Topics%20covered

Topics Covered

security advisory critical Ubuntu authentication authorization sensitivity

Package Information

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