krb5 — security advisory

{
  "id": "01879f5dfb7a0887df201a543e1dffd2a4651d80c57ec876d138e1b936cf4b08",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-40356",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-40356",
    "summary": "In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parse_message.",
    "evidence": "osv:DEBIAN-CVE-2026-40356",
    "products": [
      {
        "name": {
          "value": "krb5",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.20.1-2+deb12u5",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.20.1-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.20.1-2+deb12u1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.20.1-2+deb12u2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.20.1-2+deb12u3",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.20.1-2+deb12u4",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "krb5",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.21.3-5+deb13u1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.21.3-5",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "krb5",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.22.1-2.1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.21.3-5",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.22.1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.22.1-2",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2026-40356",
      "aliases": [
        "DEBIAN-CVE-2026-40356"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.20.1-2+deb12u5"
                }
              ]
            }
          ],
          "package": {
            "name": "krb5",
            "purl": "pkg:deb/debian/krb5?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "1.20.1-2",
            "1.20.1-2+deb12u1",
            "1.20.1-2+deb12u2",
            "1.20.1-2+deb12u3",
            "1.20.1-2+deb12u4"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40356.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.21.3-5+deb13u1"
                }
              ]
            }
          ],
          "package": {
            "name": "krb5",
            "purl": "pkg:deb/debian/krb5?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "1.21.3-5"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40356.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.22.1-2.1"
                }
              ]
            }
          ],
          "package": {
            "name": "krb5",
            "purl": "pkg:deb/debian/krb5?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "1.21.3-5",
            "1.22.1-1",
            "1.22.1-2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40356.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-27T09:47:30.155790090Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-40356"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-40356"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-40356",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 460898,
  "published_at": "2026-04-28T07:16:03.197+00:00"
}