erlang — security advisory

{
  "id": "4825907e5c77f4ae8ea04f0854420bd63d0ab9a04da1d86caaaaca1f1df4c04d",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-42791",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-42791",
    "summary": "Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid. OCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid. This affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case — server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate. This issue affects OTP from OTP 27.0 before OTP 29.0.1, OTP 28.5.0.1 and OTP 27.3.4.12, corresponding to public_key from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3.",
    "evidence": "osv:DEBIAN-CVE-2026-42791",
    "products": [
      {
        "name": {
          "value": "erlang",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:27.3.4.1+dfsg-1+deb13u3",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1:27.3.4.1+dfsg-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:27.3.4.1+dfsg-1+deb13u1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:27.3.4.1+dfsg-1+deb13u2",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "erlang",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:27.3.4.12+dfsg-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1:27.3.4.1+dfsg-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.10+dfsg-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.11+dfsg-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.11+dfsg-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.11+dfsg-3",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.11+dfsg-4",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.11+dfsg-5",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.11+dfsg-6",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.11+dfsg-7",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.3+dfsg-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.4+dfsg-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.6+dfsg-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.8+dfsg-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:27.3.4.9+dfsg-1",
            "evidence": "/affected/1/versions"
          }
        ]
      }
    ],
    "severity": "low",
    "structured": {
      "id": "DEBIAN-CVE-2026-42791",
      "aliases": [
        "DEBIAN-CVE-2026-42791"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:27.3.4.1+dfsg-1+deb13u3"
                }
              ]
            }
          ],
          "package": {
            "name": "erlang",
            "purl": "pkg:deb/debian/erlang?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "1:27.3.4.1+dfsg-1",
            "1:27.3.4.1+dfsg-1+deb13u1",
            "1:27.3.4.1+dfsg-1+deb13u2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42791.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:27.3.4.12+dfsg-1"
                }
              ]
            }
          ],
          "package": {
            "name": "erlang",
            "purl": "pkg:deb/debian/erlang?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "1:27.3.4.1+dfsg-1",
            "1:27.3.4.10+dfsg-1",
            "1:27.3.4.11+dfsg-1",
            "1:27.3.4.11+dfsg-2",
            "1:27.3.4.11+dfsg-3",
            "1:27.3.4.11+dfsg-4",
            "1:27.3.4.11+dfsg-5",
            "1:27.3.4.11+dfsg-6",
            "1:27.3.4.11+dfsg-7",
            "1:27.3.4.3+dfsg-1",
            "1:27.3.4.4+dfsg-1",
            "1:27.3.4.6+dfsg-1",
            "1:27.3.4.8+dfsg-1",
            "1:27.3.4.9+dfsg-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42791.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-27T09:47:38.586053806Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-42791"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-42791"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-42791",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 461214,
  "published_at": "2026-05-27T14:16:53.46+00:00"
}