Apache Tomcat: EncryptInterceptor not protected against replay attacks (CVE-2026-55955)
An improper authentication vulnerability in Apache Tomcat's EncryptionInterceptor component allows replay attacks in clustered environments. This affects multiple versions of Apache Tomcat from 7.0.100 through 11.0.22. The issue is fixed in Apache Tomcat versions 11.0.23, 10.1.56, and 9.0.119. Users are advised to upgrade to these fixed versions to mitigate the vulnerability.
AI Analysis
Technical Summary
CVE-2026-55955 is an improper authentication vulnerability in Apache Tomcat's EncryptionInterceptor used in the cluster component. This flaw allows an attacker to perform replay attacks against the EncryptionInterceptor, potentially bypassing intended authentication protections. The vulnerability affects Apache Tomcat versions 7.0.100 through 7.0.109, 8.5.38 through 8.5.100, 9.0.13 through 9.0.18, 10.1.0 through 10.1.55, and 11.0.0 through 11.0.22. The issue has been addressed in Apache Tomcat versions 11.0.23, 10.1.56, and 9.0.119.
Potential Impact
The vulnerability enables replay attacks on the EncryptionInterceptor in Apache Tomcat clusters, which could allow attackers to reuse intercepted authentication data to gain unauthorized access or disrupt cluster communication. The exact impact depends on the deployment and use of the cluster component but involves bypassing authentication mechanisms.
Mitigation Recommendations
A fix is available. Users should upgrade affected Apache Tomcat installations to versions 11.0.23, 10.1.56, or 9.0.119 or later to remediate this vulnerability. No additional mitigations are specified beyond applying the official patch.
Apache Tomcat: EncryptInterceptor not protected against replay attacks (CVE-2026-55955)
Description
An improper authentication vulnerability in Apache Tomcat's EncryptionInterceptor component allows replay attacks in clustered environments. This affects multiple versions of Apache Tomcat from 7.0.100 through 11.0.22. The issue is fixed in Apache Tomcat versions 11.0.23, 10.1.56, and 9.0.119. Users are advised to upgrade to these fixed versions to mitigate the vulnerability.
Affected software
pkg:deb/ubuntu/[email protected]+esm3?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/[email protected]+esm2?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/[email protected]+esm2?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]+esm4?arch=source&distro=esm-apps-legacy/xenialpkg:deb/ubuntu/[email protected]~18.04.3+esm6?arch=source&distro=esm-apps/bionicpkg:deb/ubuntu/[email protected]+esm8?arch=source&distro=esm-apps/bionicpkg:deb/ubuntu/[email protected]+esm3?arch=source&distro=esm-apps/focalpkg:deb/ubuntu/[email protected]+esm4?arch=source&distro=esm-apps/jammypkg:deb/ubuntu/[email protected]~esm4?arch=source&distro=esm-apps/noblepkg:deb/ubuntu/[email protected]+esm3?arch=source&distro=esm-apps/noblepkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]~26.04.1?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]~26.04.1?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]~26.04.1?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-55955 is an improper authentication vulnerability in Apache Tomcat's EncryptionInterceptor used in the cluster component. This flaw allows an attacker to perform replay attacks against the EncryptionInterceptor, potentially bypassing intended authentication protections. The vulnerability affects Apache Tomcat versions 7.0.100 through 7.0.109, 8.5.38 through 8.5.100, 9.0.13 through 9.0.18, 10.1.0 through 10.1.55, and 11.0.0 through 11.0.22. The issue has been addressed in Apache Tomcat versions 11.0.23, 10.1.56, and 9.0.119.
Potential Impact
The vulnerability enables replay attacks on the EncryptionInterceptor in Apache Tomcat clusters, which could allow attackers to reuse intercepted authentication data to gain unauthorized access or disrupt cluster communication. The exact impact depends on the deployment and use of the cluster component but involves bypassing authentication mechanisms.
Mitigation Recommendations
A fix is available. Users should upgrade affected Apache Tomcat installations to versions 11.0.23, 10.1.56, or 9.0.119 or later to remediate this vulnerability. No additional mitigations are specified beyond applying the official patch.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-55955
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:14.04:LTS","Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:Pro:22.04:LTS","Ubuntu:Pro:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a58b47468715ace43d8d70f
Added to database: 07/16/2026, 10:37:40 UTC
Last enriched: 09/08/2026, 15:03:00 UTC
Last updated: 09/14/2026, 22:01:35 UTC
Views: 36
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