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dovecot — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2026-40205

An attacker that holds an OAuth2 token granting only part of the required scopes can authenticate, because when more than one scope is required in the configuration, the remote token validation paths accept a token that carries only one of them, while the local token validation path correctly requires all of them. The configured authorization policy is not enforced, so a token that was granted only part of the required permissions is accepted where it should have been rejected. Use local token validation where tokens can be validated locally. Update to non-vulnerable version. No publicly available exploits are known.

Products
dovecot
Affected versions
1:2.3.19.1+dfsg1-2.1, 1:2.3.19.1+dfsg1-2.1+deb12u1, 1:2.3.19.1+dfsg1-2.1+deb12u2, 1:2.3.19.1+dfsg1-2.1+deb12u3, 1:2.3.19.1+dfsg1-2.1+deb12u4, 1:2.3.19.1+dfsg1-2.1+deb12u5, 1:2.3.19.1+dfsg1-2.1+deb12u6, 1:2.4.1+dfsg1-6, 1:2.4.1+dfsg1-6+deb13u1, 1:2.4.1+dfsg1-6+deb13u2, 1:2.4.1+dfsg1-6+deb13u3, 1:2.4.1+dfsg1-6+deb13u4, 1:2.4.1+dfsg1-6+deb13u5, 1:2.4.1+dfsg1-6+deb13u6, 1:2.4.1+dfsg1-7, 1:2.4.1+dfsg1-8, 1:2.4.1+dfsg1-9, 1:2.4.2+dfsg1-1, 1:2.4.2+dfsg1-2, 1:2.4.2+dfsg1-3, 1:2.4.2+dfsg1-4, 1:2.4.3+dfsg1-1, 1:2.4.3+dfsg1-2, 1:2.4.4+dfsg1-1, 1:2.4.4+dfsg1-2
Fixed versions
1:2.3.19.1+dfsg1-2.1+deb12u7, 1:2.4.1+dfsg1-6+deb13u7, 1:2.4.5+dfsg1-1
CVEs
CVE-2026-40205
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 01:37 UTC · Revision 1

Source evidence

DEBIAN-CVE-2026-40205

core-osv · Original source

Published 28 Aug 2026, 12:16 UTC

An attacker that holds an OAuth2 token granting only part of the required scopes can authenticate, because when more than one scope is required in the configuration, the remote token validation paths accept a token that carries only one of them, while the local token validation path correctly requires all of them. The configured authorization policy is not enforced, so a token that was granted only part of the required permissions is accepted where it should have been rejected. Use local token validation where tokens can be validated locally. Update to non-vulnerable version. No publicly available exploits are known.

osv:DEBIAN-CVE-2026-40205

dovecot

Fixed versions: 1:2.3.19.1+dfsg1-2.1+deb12u7

dovecot

Fixed versions: 1:2.4.1+dfsg1-6+deb13u7

dovecot

Fixed versions: 1:2.4.5+dfsg1-1

Complete source record
{
  "id": "2bd3ca5a6361cb01c826ae3c838d3ca9d23c865fa968bcdb80c5e55d420de623",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-40205",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-40205",
    "summary": "An attacker that holds an OAuth2 token granting only part of the required scopes can authenticate, because when more than one scope is required in the configuration, the remote token validation paths accept a token that carries only one of them, while the local token validation path correctly requires all of them. The configured authorization policy is not enforced, so a token that was granted only part of the required permissions is accepted where it should have been rejected. Use local token validation where tokens can be validated locally. Update to non-vulnerable version. No publicly available exploits are known.",
    "evidence": "osv:DEBIAN-CVE-2026-40205",
    "products": [
      {
        "name": {
          "value": "dovecot",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.3.19.1+dfsg1-2.1+deb12u7",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1:2.3.19.1+dfsg1-2.1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.3.19.1+dfsg1-2.1+deb12u1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.3.19.1+dfsg1-2.1+deb12u2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.3.19.1+dfsg1-2.1+deb12u3",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.3.19.1+dfsg1-2.1+deb12u4",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.3.19.1+dfsg1-2.1+deb12u5",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.3.19.1+dfsg1-2.1+deb12u6",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "dovecot",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.4.1+dfsg1-6+deb13u7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1:2.4.1+dfsg1-6",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u3",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u4",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u5",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u6",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "dovecot",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.4.5+dfsg1-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1:2.4.1+dfsg1-6",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-7",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-8",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-9",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.2+dfsg1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.2+dfsg1-2",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.2+dfsg1-3",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.2+dfsg1-4",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.3+dfsg1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.3+dfsg1-2",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.4+dfsg1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1:2.4.4+dfsg1-2",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2026-40205",
      "aliases": [
        "DEBIAN-CVE-2026-40205"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.3.19.1+dfsg1-2.1+deb12u7"
                }
              ]
            }
          ],
          "package": {
            "name": "dovecot",
            "purl": "pkg:deb/debian/dovecot?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "1:2.3.19.1+dfsg1-2.1",
            "1:2.3.19.1+dfsg1-2.1+deb12u1",
            "1:2.3.19.1+dfsg1-2.1+deb12u2",
            "1:2.3.19.1+dfsg1-2.1+deb12u3",
            "1:2.3.19.1+dfsg1-2.1+deb12u4",
            "1:2.3.19.1+dfsg1-2.1+deb12u5",
            "1:2.3.19.1+dfsg1-2.1+deb12u6"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40205.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.4.1+dfsg1-6+deb13u7"
                }
              ]
            }
          ],
          "package": {
            "name": "dovecot",
            "purl": "pkg:deb/debian/dovecot?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "1:2.4.1+dfsg1-6",
            "1:2.4.1+dfsg1-6+deb13u1",
            "1:2.4.1+dfsg1-6+deb13u2",
            "1:2.4.1+dfsg1-6+deb13u3",
            "1:2.4.1+dfsg1-6+deb13u4",
            "1:2.4.1+dfsg1-6+deb13u5",
            "1:2.4.1+dfsg1-6+deb13u6"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40205.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.4.5+dfsg1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "dovecot",
            "purl": "pkg:deb/debian/dovecot?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "1:2.4.1+dfsg1-6",
            "1:2.4.1+dfsg1-7",
            "1:2.4.1+dfsg1-8",
            "1:2.4.1+dfsg1-9",
            "1:2.4.2+dfsg1-1",
            "1:2.4.2+dfsg1-2",
            "1:2.4.2+dfsg1-3",
            "1:2.4.2+dfsg1-4",
            "1:2.4.3+dfsg1-1",
            "1:2.4.3+dfsg1-2",
            "1:2.4.4+dfsg1-1",
            "1:2.4.4+dfsg1-2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40205.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-31T16:04:23.691322429Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-40205"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-40205"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-40205",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 423895,
  "published_at": "2026-08-28T12:16:29.14+00:00"
}