USN-8365-1

It was discovered that Dovecot incorrectly treated some variable expansion pipelines as safe in authentication filters. An attacker could possibly use this issue to perform SQL or LDAP injection attacks. This issue only affected Ubuntu 25.10 and Ubuntu 26.04 LTS. (CVE-2026-27851)

It was discovered that Dovecot incorrectly verified SCRAM TLS channel binding in certain base64 exchanges. A remote attacker could possibly use this issue to obtain sensitive information in a machine-in-the-middle attack. (CVE-2026-33603)

It was discovered that Dovecot incorrectly enforced Sieve script CPU limits. An attacker could possibly use this issue to cause Dovecot to use excessive resources, leading to a denial of service. (CVE-2026-40016)

It was discovered that Dovecot incorrectly handled certain IMAP SETACL commands. An attacker could possibly use this issue to spam folders to other users. (CVE-2026-40020)

It was discovered that Dovecot incorrectly handled excessive IMAP bracing. An attacker could possibly use this issue to cause Dovecot to use excessive resources, leading to a denial of service. (CVE-2026-42006)

References

Affected packages

Ubuntu:22.04:LTS / dovecot

Package

Name: dovecot
Purl: pkg:deb/ubuntu/dovecot?arch=source&distro=jammy

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1:2.3.16+dfsg1-3ubuntu2.9

Affected versions

1:2.*

1:2.3.13+dfsg1-1ubuntu3

1:2.3.16+dfsg1-3ubuntu1

1:2.3.16+dfsg1-3ubuntu2

1:2.3.16+dfsg1-3ubuntu2.1

1:2.3.16+dfsg1-3ubuntu2.2

1:2.3.16+dfsg1-3ubuntu2.4

1:2.3.16+dfsg1-3ubuntu2.6

1:2.3.16+dfsg1-3ubuntu2.7

1:2.3.16+dfsg1-3ubuntu2.8

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "dovecot-auth-lua",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-core",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-gssapi",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-imapd",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-ldap",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-lmtpd",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-lucene",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-managesieved",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-mysql",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-pgsql",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-pop3d",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-sieve",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-solr",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-sqlite",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        },
        {
            "binary_name": "dovecot-submissiond",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8365-1.json"

cves_map

{
    "ecosystem": "Ubuntu:22.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-33603",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-40016",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-40020",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-42006",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:24.04:LTS / dovecot

Package

Name: dovecot
Purl: pkg:deb/ubuntu/dovecot?arch=source&distro=noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1:2.3.21+dfsg1-2ubuntu6.5

Affected versions

1:2.*

1:2.3.20+dfsg1-1ubuntu3

1:2.3.21+dfsg1-2ubuntu1

1:2.3.21+dfsg1-2ubuntu2

1:2.3.21+dfsg1-2ubuntu4

1:2.3.21+dfsg1-2ubuntu5

1:2.3.21+dfsg1-2ubuntu6

1:2.3.21+dfsg1-2ubuntu6.1

1:2.3.21+dfsg1-2ubuntu6.2

1:2.3.21+dfsg1-2ubuntu6.3

1:2.3.21+dfsg1-2ubuntu6.4

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "dovecot-auth-lua",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-core",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-gssapi",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-imapd",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-ldap",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-lmtpd",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-managesieved",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-mysql",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-pgsql",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-pop3d",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-sieve",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-solr",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-sqlite",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        },
        {
            "binary_name": "dovecot-submissiond",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8365-1.json"

cves_map

{
    "ecosystem": "Ubuntu:24.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-33603",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-40016",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-40020",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-42006",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:25.10 / dovecot

Package

Name: dovecot
Purl: pkg:deb/ubuntu/dovecot?arch=source&distro=questing

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1:2.4.1+dfsg1-5ubuntu4.2

Affected versions

1:2.*

1:2.3.21.1+dfsg1-1ubuntu2

1:2.4.1+dfsg1-5ubuntu1

1:2.4.1+dfsg1-5ubuntu3

1:2.4.1+dfsg1-5ubuntu4

1:2.4.1+dfsg1-5ubuntu4.1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "dovecot-auth-lua",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-core",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-flatcurve",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-gssapi",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-imapd",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-ldap",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-lmtpd",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-managesieved",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-mysql",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-pgsql",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-pop3d",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-sieve",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-solr",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-sqlite",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        },
        {
            "binary_name": "dovecot-submissiond",
            "binary_version": "1:2.4.1+dfsg1-5ubuntu4.2"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8365-1.json"

cves_map

{
    "ecosystem": "Ubuntu:25.10",
    "cves": [
        {
            "id": "CVE-2026-27851",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-33603",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-40016",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-40020",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-42006",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:26.04:LTS / dovecot

Package

Name: dovecot
Purl: pkg:deb/ubuntu/dovecot?arch=source&distro=resolute

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1:2.4.2+dfsg1-3ubuntu2.1

Affected versions

1:2.*

1:2.4.1+dfsg1-5ubuntu4

1:2.4.1+dfsg1-5ubuntu5

1:2.4.2+dfsg1-3ubuntu1

1:2.4.2+dfsg1-3ubuntu2

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "dovecot-auth-lua",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-core",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-flatcurve",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-gssapi",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-imapd",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-ldap",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-lmtpd",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-managesieved",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-mysql",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-pgsql",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-pop3d",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-sieve",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-solr",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-sqlite",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        },
        {
            "binary_name": "dovecot-submissiond",
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8365-1.json"

cves_map

{
    "ecosystem": "Ubuntu:26.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-27851",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-33603",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-40016",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-40020",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-42006",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}