Authentication Bypass by Capture-replay in Apache Tomcat - CVE-2026-55955

Vulnerability identifier: #VU135863

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-55955

CWE-ID: CWE-294

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to replay protected communications.

The vulnerability exists due to missing replay protection in EncryptInterceptor when processing encrypted messages. A remote attacker can capture and resend previously valid messages to replay protected communications.

Apache Tomcat
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
Web and Scripting Module
openSUSE Leap
openEuler
tomcat-help
tomcat
tomcat-jsvc
tomcat-lib
tomcat-admin-webapps
tomcat-javadoc
tomcat-servlet-4_0-api
tomcat-jsp-2_3-api
tomcat-el-3_0-api
tomcat-webapps
tomcat-docs-webapp
tomcat10-admin-webapps
tomcat10-lib
tomcat10-webapps
tomcat10-jsp-3_1-api
tomcat10-el-5_0-api
tomcat10-servlet-6_0-api
tomcat10
tomcat11-lib
tomcat11-admin-webapps
tomcat11
tomcat11-servlet-6_1-api
tomcat11-el-6_0-api
tomcat11-embed
tomcat11-jsp-4_0-api
tomcat11-webapps
tomcat11-jsvc
tomcat11-docs-webapp
tomcat11-doc

Install security update from vendor's website.

Apache Tomcat - addressed in versions 9.0.119, 10.1.56, 11.0.23
tomcat-help - update to 9.0.119-1
tomcat - update to 9.0.119-1
tomcat-jsvc - update to 9.0.119-1
tomcat-lib - addressed in versions 9.0.119-3.169.1, 9.0.119-150200.111.1
tomcat - addressed in versions 9.0.119-3.169.1, 9.0.119-150200.111.1
tomcat-admin-webapps - addressed in versions 9.0.119-3.169.1, 9.0.119-150200.111.1
tomcat-javadoc - update to 9.0.119-3.169.1
tomcat-servlet-4_0-api - addressed in versions 9.0.119-3.169.1, 9.0.119-150200.111.1
tomcat-jsp-2_3-api - addressed in versions 9.0.119-3.169.1, 9.0.119-150200.111.1
tomcat-el-3_0-api - addressed in versions 9.0.119-3.169.1, 9.0.119-150200.111.1
tomcat-webapps - addressed in versions 9.0.119-3.169.1, 9.0.119-150200.111.1
tomcat-docs-webapp - update to 9.0.119-3.169.1
tomcat10-admin-webapps - update to 10.1.56-150200.5.70.1
tomcat10-lib - update to 10.1.56-150200.5.70.1
tomcat10-webapps - update to 10.1.56-150200.5.70.1
tomcat10-jsp-3_1-api - update to 10.1.56-150200.5.70.1
tomcat10-el-5_0-api - update to 10.1.56-150200.5.70.1
tomcat10-servlet-6_0-api - update to 10.1.56-150200.5.70.1
tomcat10 - update to 10.1.56-150200.5.70.1
tomcat11-lib - update to 11.0.23-150600.13.24.1
tomcat11-admin-webapps - update to 11.0.23-150600.13.24.1
tomcat11 - update to 11.0.23-150600.13.24.1
tomcat11-servlet-6_1-api - update to 11.0.23-150600.13.24.1
tomcat11-el-6_0-api - update to 11.0.23-150600.13.24.1
tomcat11-embed - update to 11.0.23-150600.13.24.1
tomcat11-jsp-4_0-api - update to 11.0.23-150600.13.24.1
tomcat11-webapps - update to 11.0.23-150600.13.24.1
tomcat11-jsvc - update to 11.0.23-150600.13.24.1
tomcat11-docs-webapp - update to 11.0.23-150600.13.24.1
tomcat11-doc - update to 11.0.23-150600.13.24.1

• https://tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.1.56
• https://tomcat.apache.org/security-11.html#Fixed_in_Apache_Tomcat_11.0.23
• https://tomcat.apache.org/security-9.html#Fixed_in_Apache_Tomcat_9.0.119
• https://github.com/apache/tomcat/commit/3a9ff01d2dfaca651edacbda3260e37b98b540d3
• https://lists.apache.org/thread/zfxycp2d0yb4p9vdgbjctr1l06kc91jn

• Multiple vulnerabilities in Apache Tomcat
• openEuler 24.03 LTS SP3 update for tomcat
• openEuler 24.03 LTS SP1 update for tomcat
• openEuler 22.03 LTS SP4 update for tomcat
• openEuler 20.03 LTS SP4 update for tomcat
• SUSE update for tomcat11
• SUSE update for tomcat
• SUSE update for tomcat10
• SUSE update for tomcat