The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:13857 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: ManageSieve: Denial of Service via crafted SASL initial response in AUTHENTICATE command     (CVE-2025-59032)

    * dovecot: denial of service via crafted message before authentication (CVE-2026-27858)

    * dovecot: denial of service via specially crafted NOOP command (CVE-2026-27857)

    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 RockyLinux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:13498 advisory.

    * dovecot: ManageSieve: Denial of Service via crafted SASL initial response in AUTHENTICATE command     (CVE-2025-59032)

    * dovecot: denial of service via crafted message before authentication (CVE-2026-27858)

    * dovecot: denial of service via specially crafted NOOP command (CVE-2026-27857)

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 Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-13830 advisory.

    - fix CVE-2026-27858: denial of service via crafted message before authentication (RHEL-161630)
    - fix CVE-2025-59032: ManageSieve: Denial of Service via crafted SASL initial response in AUTHENTICATE     command (RHEL-162282)

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 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:17628 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: ManageSieve: Denial of Service via crafted SASL initial response in AUTHENTICATE command     (CVE-2025-59032)

    * dovecot: denial of service via crafted message before authentication (CVE-2026-27858)

    * dovecot: denial of service via specially crafted NOOP command (CVE-2026-27857)

    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 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-51dba40a65 advisory.

    updated to 2.4.3 which includes several 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 Oracle Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-19364 advisory.

    - fix CVE-2026-27858: denial of service via crafted message before authentication (RHEL-161640)
    - fix CVE-2025-59032: ManageSieve: Denial of Service via crafted SASL initial response in AUTHENTICATE     command (RHEL-162288)

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.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1570 advisory.

    Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An     attacker can use this to determine the configured credentials. Figuring out the credential will lead into     full access to the affected component. Limit access to the doveadm http service port, install fixed     version. No publicly available exploits are known. (CVE-2026-27856)

    Sending NOOP (((...))) command with 4000 parenthesis open+close results in ~1MB extra memory usage.
    Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time     periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and     create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and     killing the process and its other proxied connections. Attacker could connect possibly from even a single     IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit     and killing the process and its other proxied connections. Install fixed version, there is no other     remediation. No publicly available exploits are known. (CVE-2026-27857)

    Attacker can send a specifically crafted message before authentication that causes managesieve to allocate     large amount of memory.Attacker can force managesieve-login to be unavailable by repeatedly crashing the     process. Protect access to managesieve protocol, or install fixed version. No publicly available exploits     are known. (CVE-2026-27858)

Tenable has extracted the preceding description block directly from the tested product 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 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the CIQ crlsa-2026_13857 advisory.

    * dovecot: ManageSieve: Denial of Service via crafted SASL initial response in AUTHENTICATE command     (CVE-2025-59032)

    * dovecot: denial of service via crafted message before authentication (CVE-2026-27858)

    * dovecot: denial of service via specially crafted NOOP command (CVE-2026-27857)

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 Ubuntu 22.04 LTS / 24.04 LTS / 25.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8136-1 advisory.

    It was discovered that Dovecot incorrectly handled invalid base64 SASL data. An attacker could possibly     use this issue to cause a denial of service. This issue only affected Ubuntu 25.10. (CVE-2025-59028)

    It was discovered that Dovecot script decode2text.sh incorrectly handled zip files. An attacker could     possibly use this issue to obtain sensitive information. (CVE-2025-59031)

    It was discovered that Dovecot incorrectly handled certain AUTHENTICATE requests. An attacker could     possibly use this issue to cause a denial of service. (CVE-2025-59032)

    It was discovered that Dovecot incorrectly handled certain SQL based authentication. An attacker could     possibly use this issue to bypass authentication. This issue only affected Ubuntu 25.10. (CVE-2026-24031)

    It was discovered that Dovecot incorrectly handled certain LDAP based authentication. An attacker could     possibly use this issue to bypass restrictions and allow probing of LDAP structure. This issue only     affected Ubuntu 25.10. (CVE-2026-27860)

    It was discovered that Dovecot is vulnerable to replay attack under certain conditions. An attacker could     possibly use this issue to bypass authentication. (CVE-2026-27855)

    It was discovered that Dovecot is vulnerable to a timing attack under certain conditions. An attacker     could possibly use this issue to bypass authentication. (CVE-2026-27856)

    It was discovered that Dovecot incorrectly handled certain IMAP login requests. An attacker could possibly     use this issue to cause a denial of service. (CVE-2026-27857)

    It was discovered that Dovecot incorrectly handled certain specially crafted messages. An attacker could     possibly use this issue to cause a denial of service. (CVE-2026-27858)

    It was discovered that Dovecot incorrectly handled certain specially crafted mail messages. An attacker     could possibly use this issue to cause a denial of service. (CVE-2026-27859)

    It was discovered that Dovecot incorrectly handles file paths. A attacker could possibly use this issue to     perform a path traversal and obtain or modify arbitrary files. This issue only affected Ubuntu 22.04 LTS     and Ubuntu 24.04 LTS. (CVE-2026-0394)

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

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
312286	RHEL 9 : dovecot (RHSA-2026:13857)	Nessus	Red Hat Local Security Checks	2026/5/5	2026/5/5	high
312381	RockyLinux 10 : dovecot (RLSA-2026:13498)	Nessus	Rocky Linux Local Security Checks	2026/5/6	2026/5/6	high
312677	Oracle Linux 8 : dovecot (ELSA-2026-13830)	Nessus	Oracle Linux Local Security Checks	2026/5/6	2026/5/6	high
314751	RHEL 9 : dovecot (RHSA-2026:17628)	Nessus	Red Hat Local Security Checks	2026/5/14	2026/5/14	high
313033	Fedora 43 : dovecot (2026-51dba40a65)	Nessus	Fedora Local Security Checks	2026/5/7	2026/5/7	high
322567	Oracle Linux 9 : dovecot (ELSA-2026-19364)	Nessus	Oracle Linux Local Security Checks	2026/6/24	2026/6/24	high
306220	Amazon Linux 2023 : dovecot, dovecot-devel, dovecot-mysql (ALAS2023-2026-1570)	Nessus	Amazon Linux Local Security Checks	2026/4/13	2026/5/6	medium
355210	Rocky Linux 9 [CIQ] Security Update: dovecot / dovecot-debuginfo / dovecot-debugsource / dovecot-devel / etc Multiple Vulnerabilities (crlsa-2026_13857)	Nessus	Rocky Linux Local Security Checks	2026/10/1	2026/10/1	high
304437	Ubuntu 22.04 LTS / 24.04 LTS / 25.10 : Dovecot vulnerabilities (USN-8136-1)	Nessus	Ubuntu Local Security Checks	2026/3/31	2026/4/20	high

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