MediumFix available

TLS Hostname Verification Falls Back to CN After SAN Mismatch

Type: advisorySource: OSV1 source record

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.

Announced 1 Oct 2026Group revision 1

Original source ↗

BIT-php-2026-91769

Primary source · Revision 2

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:BIT-php-2026-91769

php

Source reference: /affected/0/package/name

Affected versions: Not stated in this record
Fixed versions: 8.2.34
Source reference: /affected/0/ranges
8.3.35
Source reference: /affected/0/ranges
8.4.26
Source reference: /affected/0/ranges
8.5.11
Source reference: /affected/0/ranges
Prerequisites: Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "SEMVER",
        "events": [
          {
            "introduced": "8.2.0"
          },
          {
            "fixed": "8.2.34"
          },
          {
            "introduced": "8.3.0"
          },
          {
            "fixed": "8.3.35"
          },
          {
            "introduced": "8.4.0"
          },
          {
            "fixed": "8.4.26"
          },
          {
            "introduced": "8.5.0"
          },
          {
            "fixed": "8.5.11"
          }
        ]
      }
    ],
    "package": {
      "name": "php",
      "purl": "pkg:bitnami/php",
      "ecosystem": "Bitnami"
    },
    "severity": [
      {
        "type": "CVSS_V3",
        "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
      }
    ],
    "database_specific": {
      "source": "https://github.com/bitnami/vulndb/tree/main/data/php/BIT-php-2026-91769.json"
    }
  }
]