Important: dovecot security, bug fix, and enhancement update

{
  "id": "a19472fad48f92f144e6a75c1589ff869cd1e12155e1eab2531b19274ba7252f",
  "url": "https://osv.dev/vulnerability/ALSA-2026%3A76763",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Important: dovecot security, bug fix, and enhancement update",
    "summary": "Dovecot is an IMAP server for Linux and other UNIX-like systems, written primarily with security in mind. It also contains a small POP3 server, and supports e-mail in either the maildir or mbox format. The SQL drivers and authentication plug-ins are provided as subpackages. Security Fix(es): * dovecot: Dovecot: Denial of Service via IMAP ID command with excessive parameters (CVE-2026-42391) * dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation (CVE-2026-73208) * dovecot: Dovecot: Denial of service via crafted email headers (CVE-2026-27852) * dovecot: Dovecot: Denial of Service via truncated quoted argument in ManageSieve (CVE-2026-40019) * dovecot: Dovecot: Denial of Service and potential message duplication via connection limit exhaustion (CVE-2026-33263) * dovecot: Dovecot: Denial of Service in ManageSieve login process (CVE-2026-33605) * dovecot: Dovecot: Arbitrary Code Execution via Sieve editheader use-after-free (CVE-2026-42007) * dovecot: Dovecot: MySQL multi-byte escaping wrong (CVE-2026-40018) Bug Fix(es) and Enhancement(s): * Dovecot crashes when accessing mailbox with: \"Panic: file mail-user.c: line 229 (mail_user_deinit): assertion failed: ((*user)->refcount == 1)\" (JIRA:AlmaLinux-176273) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.",
    "evidence": "osv:ALSA-2026:76763",
    "products": [
      {
        "name": {
          "value": "dovecot",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.3.16-16.el8_10",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "dovecot-devel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.3.16-16.el8_10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "dovecot-mysql",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.3.16-16.el8_10",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "dovecot-pgsql",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.3.16-16.el8_10",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "dovecot-pigeonhole",
          "evidence": "/affected/4/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:2.3.16-16.el8_10",
            "evidence": "/affected/4/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "ALSA-2026:76763",
      "aliases": [
        "ALSA-2026:76763"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.3.16-16.el8_10"
                }
              ]
            }
          ],
          "package": {
            "name": "dovecot",
            "purl": "pkg:rpm/almalinux/dovecot",
            "ecosystem": "AlmaLinux:8"
          },
          "database_specific": {
            "source": "https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux8/ALSA-2026:76763.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.3.16-16.el8_10"
                }
              ]
            }
          ],
          "package": {
            "name": "dovecot-devel",
            "purl": "pkg:rpm/almalinux/dovecot-devel",
            "ecosystem": "AlmaLinux:8"
          },
          "database_specific": {
            "source": "https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux8/ALSA-2026:76763.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.3.16-16.el8_10"
                }
              ]
            }
          ],
          "package": {
            "name": "dovecot-mysql",
            "purl": "pkg:rpm/almalinux/dovecot-mysql",
            "ecosystem": "AlmaLinux:8"
          },
          "database_specific": {
            "source": "https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux8/ALSA-2026:76763.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.3.16-16.el8_10"
                }
              ]
            }
          ],
          "package": {
            "name": "dovecot-pgsql",
            "purl": "pkg:rpm/almalinux/dovecot-pgsql",
            "ecosystem": "AlmaLinux:8"
          },
          "database_specific": {
            "source": "https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux8/ALSA-2026:76763.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:2.3.16-16.el8_10"
                }
              ]
            }
          ],
          "package": {
            "name": "dovecot-pigeonhole",
            "purl": "pkg:rpm/almalinux/dovecot-pigeonhole",
            "ecosystem": "AlmaLinux:8"
          },
          "database_specific": {
            "source": "https://github.com/AlmaLinux/osv-database/blob/master/advisories/almalinux8/ALSA-2026:76763.json"
          }
        }
      ],
      "modified": "2026-10-07T12:56:52.469309474Z",
      "provider": "osv",
      "references": [
        "https://access.redhat.com/errata/RHSA-2026:76763",
        "https://access.redhat.com/security/cve/CVE-2026-27852",
        "https://access.redhat.com/security/cve/CVE-2026-33263",
        "https://access.redhat.com/security/cve/CVE-2026-33605",
        "https://access.redhat.com/security/cve/CVE-2026-40018",
        "https://access.redhat.com/security/cve/CVE-2026-40019",
        "https://access.redhat.com/security/cve/CVE-2026-42007",
        "https://access.redhat.com/security/cve/CVE-2026-42391",
        "https://access.redhat.com/security/cve/CVE-2026-73208",
        "https://bugzilla.redhat.com/2525545",
        "https://bugzilla.redhat.com/2525547",
        "https://bugzilla.redhat.com/2525557",
        "https://bugzilla.redhat.com/2525559",
        "https://bugzilla.redhat.com/2525567",
        "https://bugzilla.redhat.com/2525576",
        "https://bugzilla.redhat.com/2525583",
        "https://bugzilla.redhat.com/2525584",
        "https://errata.almalinux.org/8/ALSA-2026-76763.html"
      ]
    },
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 95032,
  "published_at": "2026-10-06T00:00:00+00:00"
}