Bug 2543804

Summary: CVE-2026-91769 php: php: Server impersonation via Common Name fallback in TLS verification [fedora-all]
Product: [Fedora] Fedora Reporter: Ganesh <gnaik>
Component: phpAssignee: Remi Collet <fedora>
Status: CLOSED RAWHIDE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: fedora, jorton
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["2b1d478f-be3a-4119-ad0d-ce6250f9a2b1"]}
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Clone Of: Environment:
Last Closed: 2026-10-01 08:44:00 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2542493    

Description Ganesh 2026-09-30 05:48:47 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

PHP's OpenSSL stream peer verification checks the certificate's subjectAltName entries first and, whenever no entry matches, falls back to the Common Name. RFC 6125 requires the CN to be ignored once the certificate presents any service identity, so a certificate carrying a non-matching DNS SAN was still accepted when its CN matched the requested peer_name. A certificate trusted by the client for one name can therefore be used to impersonate another.
Comment 1 Remi Collet 2026-10-01 08:44:00 UTC 
PHP 8.4.26 (F43) and 8.5.11 (F44) already in stable repository