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CVE-2026-91769

Full vulnerability record from the local CVENow database.

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.

Severity
MEDIUM
CVSS score
4.3 (v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-09-25 21:17:24.913000
Last modified
2026-10-23 13:20:43.460000
View original CVE JSON
{
  "id": "CVE-2026-91769",
  "sourceIdentifier": "[email protected]",
  "published": "2026-09-25T21:17:24.913",
  "lastModified": "2026-10-23T13:20:43.460",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "PHP Group",
          "product": "PHP",
          "defaultStatus": "unaffected",
          "packageName": "ext-openssl",
          "versions": [
            {
              "version": "8.2.*",
              "lessThan": "8.2.34",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "8.3.*",
              "lessThan": "8.3.35",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "8.4.*",
              "lessThan": "8.4.26",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "8.5.*",
              "lessThan": "8.5.11",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "ADJACENT_NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-09-28T12:56:47.310384Z",
          "id": "CVE-2026-91769",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-297"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "8.2.0",
              "versionEndExcluding": "8.2.34",
              "matchCriteriaId": "AAFB3643-4D71-46ED-8184-DDE5FE41CD02"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "8.3.0",
              "versionEndExcluding": "8.3.35",
              "matchCriteriaId": "FF664EE8-D417-45A4-84DF-158F5073FDE8"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "8.4.0",
              "versionEndExcluding": "8.4.26",
              "matchCriteriaId": "52D4BECA-EF0D-4180-837C-AEFA7A12D243"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "8.5.0",
              "versionEndExcluding": "8.5.11",
              "matchCriteriaId": "308803C0-9FC8-40D2-8920-B83BCC48014F"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/php/php-src/security/advisories/GHSA-vvx9-73fr-5jjx",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory",
        "Exploit"
      ]
    }
  ]
}