UBUNTU-CVE-2026-27857

See a problem?
Please try reporting it to the source first.

Source

https://ubuntu.com/security/CVE-2026-27857

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27857.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-27857

Upstream

CVE-2026-27857

Related

USN-8136-1

Published

2026-03-27T00:00:00Z

Modified

2026-04-22T16:27:44.550183Z

Severity

4.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
Ubuntu - medium

Summary

[none]

Details

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.

References

Affected packages

Ubuntu:20.04:LTS / dovecot

Package

Name: dovecot
Purl: pkg:deb/ubuntu/dovecot@1:2.3.7.2-1ubuntu3.7?arch=source&distro=focal

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1:2.*

1:2.3.4.1-5ubuntu3

1:2.3.7.2-1ubuntu1

1:2.3.7.2-1ubuntu2

1:2.3.7.2-1ubuntu3

1:2.3.7.2-1ubuntu3.1

1:2.3.7.2-1ubuntu3.2

1:2.3.7.2-1ubuntu3.3

1:2.3.7.2-1ubuntu3.4

1:2.3.7.2-1ubuntu3.5

1:2.3.7.2-1ubuntu3.6

1:2.3.7.2-1ubuntu3.7

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "dovecot-auth-lua",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-core",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-gssapi",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-imapd",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-ldap",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-lmtpd",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-lucene",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-managesieved",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-mysql",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-pgsql",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-pop3d",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-sieve",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-solr",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-sqlite",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "dovecot-submissiond",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        },
        {
            "binary_name": "mail-stack-delivery",
            "binary_version": "1:2.3.7.2-1ubuntu3.7"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27857.json"

Ubuntu:22.04:LTS / dovecot

Package

Name: dovecot
Purl: pkg:deb/ubuntu/dovecot@1:2.3.16+dfsg1-3ubuntu2.7?arch=source&distro=jammy

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1:2.3.16+dfsg1-3ubuntu2.7

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

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "dovecot-auth-lua",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-core",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-gssapi",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-imapd",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-ldap",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-lmtpd",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-lucene",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-managesieved",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-mysql",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-pgsql",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-pop3d",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-sieve",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-solr",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-sqlite",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        },
        {
            "binary_name": "dovecot-submissiond",
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.7"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27857.json"

Ubuntu:24.04:LTS / dovecot

Package

Name: dovecot
Purl: pkg:deb/ubuntu/dovecot@1:2.3.21+dfsg1-2ubuntu6.3?arch=source&distro=noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1:2.3.21+dfsg1-2ubuntu6.3

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

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "dovecot-auth-lua",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-core",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-gssapi",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-imapd",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-ldap",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-lmtpd",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-managesieved",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-mysql",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-pgsql",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-pop3d",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-sieve",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-solr",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-sqlite",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        },
        {
            "binary_name": "dovecot-submissiond",
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.3"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27857.json"

Ubuntu:25.10 / dovecot

Package

Name: dovecot
Purl: pkg:deb/ubuntu/dovecot@1:2.4.1+dfsg1-5ubuntu4.1?arch=source&distro=questing

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1:2.4.1+dfsg1-5ubuntu4.1

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

Ecosystem specific

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

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27857.json"