The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:80825 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 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 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 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 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 remote MiracleLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2026-2032:07 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)

Tenable has extracted the preceding description block directly from the MiracleLinux 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 AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1792570553 advisory.

  - An attacker that can send mail to a user can craft a message whose headers contain a very large number of     email addresses or MIME parameters, which causes excessive memory usage when the message is later parsed.
    The message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and     terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No     publicly available exploits are known. (CVE-2026-27852)

  - When mail_max_userip_connections is set (default 10) and reached, submission-login can crash with epoll()     panic caused by file descriptor handling issues. If running in high-security mode (default for community     releases), only the new submission connection gets terminated. If running in high-performance mode     (default for Pro releases), all connections handled by the submission-login process will be terminated.
    The crashes can cause failure for user to send a message, or it can cause duplicate messages to be sent.
    If TLS is not used (in the backend server processing the submission), duplicate deliveries cannot happen,     because the crash can only happen at AUTH stage. Limit the number of connections handled by single     submission-login process. This has a performance impact though. Update to non-vulnerable version. No     publicly available exploits are known. (CVE-2026-33263)

  - An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command     before authenticating. If running in high-security mode (default for community releases), only the     attacker's own connection is terminated. If running in high-performance mode (default for Pro releases),     all connections handled by the same managesieve-login process are terminated. Repeating the attack can     cause denial of service for Sieve script management. Restrict network access to the ManageSieve service to     trusted clients. Update to non-vulnerable version. No publicly available exploits are known.
    (CVE-2026-33605)

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

  - An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a     use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the     delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery,     which can crash the delivery process and may allow execution of arbitrary code in the context of that     process. Disable the Sieve editheader extension. Update to non-vulnerable version. No publicly available     exploits are known. (CVE-2026-42007)

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 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1793307649 advisory.

  - An attacker that can send mail to a user can craft a message whose headers contain a very large number of     email addresses or MIME parameters, which causes excessive memory usage when the message is later parsed.
    The message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and     terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No     publicly available exploits are known. (CVE-2026-27852)

  - When mail_max_userip_connections is set (default 10) and reached, submission-login can crash with epoll()     panic caused by file descriptor handling issues. If running in high-security mode (default for community     releases), only the new submission connection gets terminated. If running in high-performance mode     (default for Pro releases), all connections handled by the submission-login process will be terminated.
    The crashes can cause failure for user to send a message, or it can cause duplicate messages to be sent.
    If TLS is not used (in the backend server processing the submission), duplicate deliveries cannot happen,     because the crash can only happen at AUTH stage. Limit the number of connections handled by single     submission-login process. This has a performance impact though. Update to non-vulnerable version. No     publicly available exploits are known. (CVE-2026-33263)

  - An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command     before authenticating. If running in high-security mode (default for community releases), only the     attacker's own connection is terminated. If running in high-performance mode (default for Pro releases),     all connections handled by the same managesieve-login process are terminated. Repeating the attack can     cause denial of service for Sieve script management. Restrict network access to the ManageSieve service to     trusted clients. Update to non-vulnerable version. No publicly available exploits are known.
    (CVE-2026-33605)

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

  - An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before     logging in, which causes memory and CPU usage to grow disproportionately. The login process can be     terminated by the out-of-memory handling, which also terminates all other connections handled by the same     process. This can cause degradation or denial of service for IMAP logins. Limit the number of connections     handled by a single imap-login process. This has a performance impact though. Update to non-vulnerable     version. No publicly available exploits are known. (CVE-2026-42391)

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

ID	名前	製品	ファミリー	公開日	更新日	深刻度
369254	RHEL 9 : dovecot (RHSA-2026:80825)	Nessus	Red Hat Local Security Checks	2026/10/21	2026/10/21	critical
348271	Fedora 45 : dovecot (2026-8b8efbd2b8)	Nessus	Fedora Local Security Checks	2026/9/18	2026/10/23	critical
363927	AlmaLinux 8 : dovecot (ALSA-2026:76763)	Nessus	Alma Linux Local Security Checks	2026/10/7	2026/10/7	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	2026/10/8	2026/10/8	critical
364314	RHEL 10 : dovecot (RHSA-2026:79371)	Nessus	Red Hat Local Security Checks	2026/10/9	2026/10/9	critical
365340	MiracleLinux 8 : dovecot-2.3.16-16.el8_10 (AXSA:2026-2032:07)	Nessus	Miracle Linux Local Security Checks	2026/10/13	2026/10/15	critical
369484	AlmaLinux 9.2 [TuxCare] Security Update: dovecot / dovecot-devel / dovecot-mysql / dovecot-pgsql / etc Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1792570553)	Nessus	Alma Linux Local Security Checks	2026/10/21	2026/10/21	critical
373911	Rocky Linux 9.6 [TuxCare] Security Update: dovecot / dovecot-devel / dovecot-mysql / dovecot-pgsql / etc Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1793307649)	Nessus	Rocky Linux Local Security Checks	2026/10/29	2026/11/2	high

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