ALSA-2026:76763

Vulnerability from osv_almalinux – Published: 2026-10-06 00:00 – Updated: 2026-10-07 07:32 – Source website
VLAI
Summary
Important: dovecot security, bug fix, and enhancement update
Details

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.

References
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "dovecot"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:2.3.16-16.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "dovecot-devel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:2.3.16-16.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "dovecot-mysql"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:2.3.16-16.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "dovecot-pgsql"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:2.3.16-16.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "AlmaLinux:8",
        "name": "dovecot-pigeonhole"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:2.3.16-16.el8_10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "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.   \n\nSecurity Fix(es):  \n\n  * dovecot: Dovecot: Denial of Service via IMAP ID command with excessive parameters (CVE-2026-42391)\n  * dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation (CVE-2026-73208)\n  * dovecot: Dovecot: Denial of service via crafted email headers (CVE-2026-27852)\n  * dovecot: Dovecot: Denial of Service via truncated quoted argument in ManageSieve (CVE-2026-40019)\n  * dovecot: Dovecot: Denial of Service and potential message duplication via connection limit exhaustion (CVE-2026-33263)\n  * dovecot: Dovecot: Denial of Service in ManageSieve login process (CVE-2026-33605)\n  * dovecot: Dovecot: Arbitrary Code Execution via Sieve editheader use-after-free (CVE-2026-42007)\n  * dovecot: Dovecot: MySQL multi-byte escaping wrong (CVE-2026-40018)\n\n\nBug Fix(es) and Enhancement(s):  \n\n  * Dovecot crashes when accessing mailbox with: \"Panic: file mail-user.c: line 229 (mail_user_deinit): assertion failed: ((*user)-\u003erefcount == 1)\" (JIRA:AlmaLinux-176273)\n\n\nFor 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.\n",
  "id": "ALSA-2026:76763",
  "modified": "2026-10-07T07:32:56Z",
  "published": "2026-10-06T00:00:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:76763"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-27852"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-33263"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-33605"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-40018"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-40019"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-42007"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-42391"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-73208"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2525545"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2525547"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2525557"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2525559"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2525567"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2525576"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2525583"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2525584"
    },
    {
      "type": "ADVISORY",
      "url": "https://errata.almalinux.org/8/ALSA-2026-76763.html"
    }
  ],
  "related": [
    "CVE-2026-42391",
    "CVE-2026-73208",
    "CVE-2026-27852",
    "CVE-2026-40019",
    "CVE-2026-33263",
    "CVE-2026-33605",
    "CVE-2026-42007",
    "CVE-2026-40018"
  ],
  "summary": "Important: dovecot security, bug fix, and enhancement update"
}



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