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Advisory severityMedium6.5Red Hat Linux

Medium [CVE-2026-55956] Improper Authorization Allows Security Constraint Bypass

This medium-severity Red Hat Linux advisory covers CVE-2026-55956 affecting Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 8.8 Telecommunications Update Service, Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-55956 Source published Source updated

VulniPulse record published Record updated

CVE-2026-55956
Affected products & platforms
Red Hat LinuxRed Hat Enterprise Linux
Open source advisory

Summary

Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected.

Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue. A flaw was found in Apache Tomcat where access control rules for the default servlet are improperly handled.

An attacker can exploit this issue to bypass specific HTTP method restrictions, potentially gaining unauthorized access to protected application resources. Red Hat products utilizing affected Tomcat versions are vulnerable if they rely on these method-specific security constraints.

Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N). Weakness: CWE-551.

Affected products named by the advisory: Red Hat Enterprise Linux 10.0 Extended Update Support; Red Hat Enterprise Linux 8.8 Telecommunications Update Service; Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions; Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions; and 17 more.

Is CVE-2026-55956 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-55956 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-55956?

Upgrade to a fixed release named by Red Hat:

  • 11.0.23
  • 10.1.56
  • 9.0.119
  • tomcat9-1:9.0.120-1.el10_2
  • tomcat9-1:9.0.120-1.el10_0
  • tomcat-1:9.0.120-1.el8_10
  • tomcat-1:9.0.120-1.el8_8
  • tomcat-1:9.0.120-2.el9_8
  • tomcat-1:9.0.120-1.el9_2
  • tomcat-1:9.0.120-1.el9_4
  • tomcat-1:9.0.120-1.el9_6
  • tomcat-catalina

22 more fixed releases are listed below.

Confirm against the vendor advisory before you patch.

Affected versions
  • 11.0.0
  • 11.0.22
  • 10.1.0
  • 10.1.55
  • 9.0.0
  • 9.0.118
  • 8.5.0
  • 8.5.100
  • 7.0.0
  • 7.0.109

Official advisory · high-confidence parse· fetched 12 days ago·verify at source

Fixed versions
  • 11.0.23
  • 10.1.56
  • 9.0.119
  • tomcat9-1:9.0.120-1.el10_2
  • tomcat9-1:9.0.120-1.el10_0
  • tomcat-1:9.0.120-1.el8_10
  • tomcat-1:9.0.120-1.el8_8
  • tomcat-1:9.0.120-2.el9_8
  • tomcat-1:9.0.120-1.el9_2
  • tomcat-1:9.0.120-1.el9_4
  • tomcat-1:9.0.120-1.el9_6
  • tomcat-catalina
  • jws6-tomcat-0:10.1.49-15.redhat_00013.1.el10jws
  • jws6-tomcat-0:10.1.49-15.redhat_00013.1.el8jws
  • jws6-tomcat-0:10.1.49-15.redhat_00013.1.el9jws
  • jws7-tomcat-0:11.0.21-5.redhat_00004.1.el10jws
  • jws7-tomcat-0:11.0.21-5.redhat_00004.1.el8jws
  • jws7-tomcat-0:11.0.21-5.redhat_00004.1.el9jws
  • tomcat10-main-10.1.56-1.hum1
  • tomcat11-main-11.0.23-0.1.hum1
  • RHSA-2026:68651
  • RHSA-2026:67163
  • RHSA-2026:68677
  • RHSA-2026:68680
  • RHSA-2026:68660
  • RHSA-2026:68678
  • RHSA-2026:68679
  • RHSA-2026:68659
  • RHSA-2026:43402
  • RHSA-2026:43401
  • RHSA-2026:39189
  • RHSA-2026:39188
  • RHSA-2026:29203
  • RHSA-2026:32960

Official advisory · high-confidence parse· fetched 12 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • Review your application's web.xml file. Ensure security constraints explicitly deny unauthorized users by path, rather than relying strictly on filtering specific HTTP methods (like GET or POST).

Official advisory · high-confidence parse· fetched 12 days ago·verify at source

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