None None None No publicly available exploits are known.

alma_linux ALSA-2026:79371: ALSA-2026:79371: dovecot security update (High)

The remote Oracle Linux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-79371 advisory.

    - fix CVE-2026-33605: ManageSieve: denial of service via lone CR       character causing protocol deadlock (RHEL-251984)
    - fix CVE-2026-42007: fix use-after-free and info leak in sieve       editheader extension (RHEL-251945)
    - fix CVE-2026-40018: incorrect escaping of multi-byte strings in SQL commands (RHEL-252058)
    - fix CVE-2026-42391: fix excessive memory growth with pre-login ID       command (RHEL-252072)
    - fix CVE-2026-73208: OAuth2 scope check requires all configured scopes, add oauth2_audience setting     (RHEL-251900)
    - fix CVE-2026-27852: limit parsed message data to prevent memory exhaustion (RHEL-251564)

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:79371 advisory.

    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)

    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.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Rocky Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the CIQ crlsa-2026_76763 advisory.

    * 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:Rocky Linux-176273)

Tenable has extracted the preceding description block directly from the CIQ security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:76763 advisory.

    * 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)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-76763 advisory.

    - fix CVE-2026-33605: ManageSieve login deadlock caused by lone CR       protocol violation (RHEL-251995)
    - fix CVE-2026-42007: heap use-after-free in pigeonhole edit_mail_snapshot       after deleteheader operation (RHEL-251946)
    - fix CVE-2026-40018: incorrect escaping of multi-byte strings in SQL commands (RHEL-252064)
    - fix CVE-2026-42391: pre-auth CPU/memory amplification via       excessive ID command key/value pairs (RHEL-252056)
    - fix CVE-2026-73208: OAuth2 scope check requires all configured scopes, add oauth2_audience setting     (RHEL-251905)
    - fix CVE-2026-27852: denial of service via memory exhaustion from       crafted message headers (RHEL-251573)
    - fix CVE-2026-33263: submission-login panic at       mail_max_userip_connections limit (RHEL-251922)

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote RockyLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:76763 advisory.

    * 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:Rocky Linux-176273)

Tenable has extracted the preceding description block directly from the RockyLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:76763 advisory.

    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:RHEL-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.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-6526 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6526-1                   security@debian.org     https://www.debian.org/security/                       Moritz Muehlenhoff     September 28, 2026                    https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : dovecot     CVE ID         : CVE-2026-27852 CVE-2026-33263 CVE-2026-33604 CVE-2026-33605                      CVE-2026-33606 CVE-2026-33607 CVE-2026-40013 CVE-2026-40014                      CVE-2026-40015 CVE-2026-40017 CVE-2026-40018 CVE-2026-40203                      CVE-2026-40204 CVE-2026-40205 CVE-2026-42007 CVE-2026-42008                      CVE-2026-42391 CVE-2026-42392 CVE-2026-42393 CVE-2026-42394                      CVE-2026-42395 CVE-2026-52681 CVE-2026-52687 CVE-2026-73208                      CVE-2026-73209     Debian Bug     : 1144639

    Multiple vulnerabilities have been discovered in the Dovecot IMAP server     which could result in denial of service, SMTP smuggling, information     disclosure, code injection via malformed Sieve scripts or bypass of ACL     restrictions.

    For the stable distribution (trixie), these problems have been fixed in     version 1:2.4.1+dfsg1-6+deb13u7.

    We recommend that you upgrade your dovecot packages.

    For the detailed security status of dovecot please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/dovecot

    Further information about Debian Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 45 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-8b8efbd2b8 advisory.

    - updated to 2.4.5, many security fixes

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-2e6b786570 advisory.

    - updated to 2.4.5, many security fixes

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-e8a6485109 advisory.

    - updated to 2.4.5, many security fixes

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote openSUSE 16 host has packages installed that are affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:21720-1 advisory.

    Update to 2.4.5.

    - CVE-2026-33263: `submission-login`: panic when `mail_max_userip_connections` is reached (bsc#1276794).
    - CVE-2026-27852: DoS by sending mail with bad header (bsc#1276799).
    - CVE-2026-33604: SMTP smuggling via missing dot-stuffing after bare carriage return (bsc#1276802).
    - CVE-2026-33605: `managesieve-login`: pre-auth crash (bsc#1276809).
    - CVE-2026-33606: `dsync`: mail content can cause `dsync` protocol injection (bsc#1276800).
    - CVE-2026-33607: IMAP `LIST` `match_sub()` exponential backtracking leading to CPU denial of service     (bsc#1276795).
    - CVE-2026-40013: stack buffer underflow in `pigeonhole` `ManageSieve` `CHECKSCRIPT/PUTSCRIPT`     (bsc#1276807).
    - CVE-2026-40014: CPU DoS via crafted references header (bsc#1276804).
    - CVE-2026-40015: `imap-hibernate` can be crashed (bsc#1276812).
    - CVE-2026-40017: CPU DoS via CRC32 hash collision in `strmap` (bsc#1276813).
    - CVE-2026-40018: MySQL multi-byte escaping performed incorrectly (bsc#1276810).
    - CVE-2026-40203: IMAP compression can reveal whether a small synced email body matches sender-chosen text       (bsc#1276815).
    - CVE-2026-40204: `lda_mailbox_autocreate` can bypass ACL restrictions (bsc#1276819).
    - CVE-2026-40205: OAuth2 `passdb` scope enforcement bypass via OR semantics in remote validation path     (bsc#1276820).
    - CVE-2026-42007: `sieve` `editheader` RCE (bsc#1276817).
    - CVE-2026-42008: `XCLIENT FORWARD= bare` token not namespaced (bsc#1276824).
    - CVE-2026-42391: `imap`: pre-login memory/CPU growth with `ID` command (bsc#1276835).
    - CVE-2026-42392: `imap-urlauth` leaks memory into user-visible error messages (bsc#1276829).
    - CVE-2026-42393: `doveadm_password` or api key length can be leaked with timing comparisons     (bsc#1276827).
    - CVE-2026-52687: `imap`: `COMPRESS ZSTD` can cause excessive memory usage (bsc#1276837).
    - CVE-2026-42395: single NUL-byte `XCLIENT FORWARD` payload crashes (bsc#1276826).
    - CVE-2026-52681: `sieve` resource usage tracking lost when active script changes (bsc#1276828).
    - CVE-2026-73208: `auth`: `db-oauth2`: `aud` claim used as fallback for missing scope claim (bsc#1276830).
    - CVE-2026-73209: `imap-login` crash due to self-recursion on zero-output decompress chunks (bsc#1276833).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - None None None No publicly available exploits are known. (CVE-2026-40018)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
364354	Oracle Linux 10 : dovecot (ELSA-2026-79371)	Nessus	Oracle Linux Local Security Checks	Local	critical
364314	RHEL 10 : dovecot (RHSA-2026:79371)	Nessus	Red Hat Local Security Checks	Local	critical
364192	Rocky Linux 8 [CIQ] Security Update: dovecot / dovecot-debuginfo / dovecot-debugsource / dovecot-devel / etc Multiple Vulnerabilities (crlsa-2026_76763)	Nessus	Rocky Linux Local Security Checks	Local	critical
363927	AlmaLinux 8 : dovecot (ALSA-2026:76763)	Nessus	Alma Linux Local Security Checks	Local	critical
363755	Oracle Linux 8 : dovecot (ELSA-2026-76763)	Nessus	Oracle Linux Local Security Checks	Local	critical
363744	RockyLinux 8 : dovecot (RLSA-2026:76763)	Nessus	Rocky Linux Local Security Checks	Local	critical
363392	RHEL 8 : dovecot (RHSA-2026:76763)	Nessus	Red Hat Local Security Checks	Local	critical
350920	Debian dsa-6526 : dovecot-auth-lua - security update	Nessus	Debian Local Security Checks	Local	critical
348271	Fedora 45 : dovecot (2026-8b8efbd2b8)	Nessus	Fedora Local Security Checks	Local	critical
348254	Fedora 44 : dovecot (2026-2e6b786570)	Nessus	Fedora Local Security Checks	Local	critical
348253	Fedora 43 : dovecot (2026-e8a6485109)	Nessus	Fedora Local Security Checks	Local	critical
342588	openSUSE 16: dovecot24 / dovecot24-backend-mysql / dovecot24-backend-pgsql / etc (openSUSE-SU-2026:21720-1)	Nessus	SuSE Local Security Checks	Local	critical
341528	Linux Distros Unpatched Vulnerability : CVE-2026-40018	Nessus	Misc.	Local	high

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