dovecot — security advisory

{
  "id": "1d9debe33356acd5f423c8d5e611b2f9a5c6168850d6864552a50db56f7984d3",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-27860",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-27860",
    "summary": "If auth_username_chars is empty, it is possible to inject arbitrary LDAP filter to Dovecot's LDAP authentication. This leads to potentially bypassing restrictions and allows probing of LDAP structure. Do not clear out auth_username_chars, or install fixed version. No publicly available exploits are known.",
    "evidence": "osv:DEBIAN-CVE-2026-27860",
    "products": [
      {
        "name": {
          "value": "dovecot",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.4.1+dfsg1-6+deb13u4",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1:2.4.1+dfsg1-6",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-6+deb13u3",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "dovecot",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.4.3+dfsg1-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1:2.4.1+dfsg1-6",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-7",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-8",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.1+dfsg1-9",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.2+dfsg1-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.2+dfsg1-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.2+dfsg1-3",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:2.4.2+dfsg1-4",
            "evidence": "/affected/1/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2026-27860",
      "aliases": [
        "DEBIAN-CVE-2026-27860"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.4.1+dfsg1-6+deb13u4"
                }
              ]
            }
          ],
          "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"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-27860.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.4.3+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"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-27860.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-26T11:47:29.928872349Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-27860"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-27860"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-27860",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 450744,
  "published_at": "2026-03-27T09:16:20.383+00:00"
}