High [CVE-2026-65927] Access control bypass due to off-by-one error in RewriteValve [N] flag processing
This high-severity Red Hat Linux advisory covers CVE-2026-65927 affecting Red Hat JBoss Web Server 5, Red Hat JBoss Web Server 6, Red Hat JBoss Web Server 7.
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Summary
Off-by-one Error vulnerability in Apache Tomcat impacting the [N] flag on the rewrite valves causes rewrite processing to restart at the second rule rather than the first rule. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.24, from 10.1.0-M1 through 10.1.57, from 9.0.0.M1 through 9.0.120.
The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100. Other unsupported versions may also be affected.
Users are recommended to upgrade to version 11.0.25, 10.1.58 or 9.0.121 which fix the issue. This vulnerability may allow an attacker to bypass intended access controls.
This vulnerability can lead to an access control bypass, allowing unauthorized access to resources in applications that utilize the RewriteValve with the [N] flag. Red Hat severity: Important — CVSS 8.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N).
Weakness: CWE-193. Affected Red Hat products: Red Hat JBoss Web Server 5; Red Hat JBoss Web Server 6; Red Hat JBoss Web Server 7.
Under investigation: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Hardened Images. Will not fix / out of support: Red Hat JBoss Web Server 5.
Red Hat does not currently list a fixing RHSA for this CVE.
- 11.0.0
- 11.0.24
- 10.1.0
- 10.1.57
- 9.0.0
- 9.0.120
- 8.5.0
- 8.5.100
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
- 11.0.25
- 10.1.58
- 9.0.121
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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