What’s Vulnerable › Vulnerabilities

CVE-2026-55955: Apache Tomcat: EncryptInterceptor not protected against replay attacks

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-29 · updated 2026-10-25
• Weakness: CWE-287

Description

Improper Authentication vulnerability in Apache Tomcat allowed a replay attack against the EncryptionInterceptor in the cluster component. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.13 through 9.0.18, from 8.5.38 through 8.5.100, from 7.0.100 through 7.0.109. Users are recommended to upgrade to version 11.0.23, 10.1.56, 9.0.119, which fixes the issue.

Affected products

• Apache Tomcat: before 9.0.119; from 10.1.0 before 10.1.56; from 11.0.0 before 11.0.23 — fixed in 9.0.119, 10.1.56, 11.0.23

How to fix

Upgrade to a fixed version: Apache Tomcat 9.0.119, 10.1.56, 11.0.23. Check the vendor advisory for mitigations.

References

• https://lists.apache.org/thread/g4p5sf45p3f9r011pwqs9r54yd64s106
• http://www.openwall.com/lists/oss-security/2026/06/29/24

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