Improper access control in Apache Tomcat - CVE-2026-65637

Vulnerability identifier: #VU145381

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-2026-65637

CWE-ID: CWE-284

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to bypass strict SNI validation.

The vulnerability exists due to improper access control in the HTTP/2 request handling when processing requests without an authority field. A remote attacker can send a specially crafted HTTP/2 request to bypass strict SNI validation.

The issue is related to an incomplete fix for a previous vulnerability.

Apache Tomcat
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise High Performance Computing 12
Web and Scripting Module
ApplinX
tomcat-jsp-2_3-api
tomcat-el-3_0-api
tomcat-javadoc
tomcat-webapps
tomcat-docs-webapp
tomcat-admin-webapps
tomcat
tomcat-lib
tomcat-servlet-4_0-api

Install security update from vendor's website.

Apache Tomcat - addressed in versions 9.0.121, 10.1.59, 11.0.25
tomcat-jsp-2_3-api - addressed in versions 9.0.121-3.177.3, 9.0.121-150200.120.1
tomcat-el-3_0-api - addressed in versions 9.0.121-3.177.3, 9.0.121-150200.120.1
tomcat-javadoc - update to 9.0.121-3.177.3
tomcat-webapps - addressed in versions 9.0.121-3.177.3, 9.0.121-150200.120.1
tomcat-docs-webapp - update to 9.0.121-3.177.3
tomcat-admin-webapps - addressed in versions 9.0.121-3.177.3, 9.0.121-150200.120.1
tomcat - addressed in versions 9.0.121-3.177.3, 9.0.121-150200.120.1
tomcat-lib - addressed in versions 9.0.121-3.177.3, 9.0.121-150200.120.1
tomcat-servlet-4_0-api - addressed in versions 9.0.121-3.177.3, 9.0.121-150200.120.1

• https://lists.apache.org/api/email.lua?id=dch3wv5ol5t8o4cymh9kbkzrj732prhc
• https://tomcat.apache.org/security-11.html

• Multiple vulnerabilities in Apache Tomcat
• SUSE update for tomcat
• SUSE update for tomcat
• Multiple vulnerabilities in IBM ApplinX