CVE-2026-91769

CVE Details

Release Date:	2026-09-25
Impact:	Moderate	What is this?

Description

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.

See more information about CVE-2026-91769 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	4.3
Vector String:	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Version:	3.1
Attack Vector:	Adjacent_Network
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	Low
Integrity Impact:	None
Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 8 (libzip)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pear)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-apcu)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-rrd)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-xdebug)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-zip)	ELSA-2026-87080	2026-10-21