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.
Advisories
| Source | ID | Title |
|---|---|---|
Debian DSA |
DSA-6514-1 | php8.4 security update |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Sat, 26 Sep 2026 08:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Php Group
Php Group php |
|
| Vendors & Products |
Php Group
Php Group php |
Fri, 25 Sep 2026 21:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | TLS Hostname Verification Falls Back to CN After SAN Mismatch | |
| Weaknesses | CWE-297 | |
| References |
| |
| Metrics |
cvssV3_1
|
Projects
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Status: PUBLISHED
Assigner: php
Published:
Updated: 2026-09-25T20:59:39.727Z
Reserved: 2026-09-15T00:44:10.816Z
Link: CVE-2026-91769
No data.
Status : Received
Published: 2026-09-25T21:17:24.913
Modified: 2026-09-25T21:17:24.913
Link: CVE-2026-91769
No data.
OpenCVE Enrichment
Updated: 2026-09-26T08:30:02Z
Weaknesses
Debian DSA