UBUNTU-CVE-2026-42391

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Source
https://ubuntu.com/security/CVE-2026-42391
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42391.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-42391
Upstream
  • CVE-2026-42391
Published
2026-08-28T00:00:00Z
Modified
2026-09-02T19:36:04.963478078Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:16.04:LTS
dovecot

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1:2.*
1:2.2.18-2ubuntu2
1:2.2.22-1ubuntu1
1:2.2.22-1ubuntu2
1:2.2.22-1ubuntu2.1
1:2.2.22-1ubuntu2.2
1:2.2.22-1ubuntu2.3
1:2.2.22-1ubuntu2.4
1:2.2.22-1ubuntu2.6
1:2.2.22-1ubuntu2.7
1:2.2.22-1ubuntu2.8
1:2.2.22-1ubuntu2.9
1:2.2.22-1ubuntu2.10
1:2.2.22-1ubuntu2.11
1:2.2.22-1ubuntu2.12
1:2.2.22-1ubuntu2.13
1:2.2.22-1ubuntu2.14

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-core"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-gssapi"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-imapd"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-ldap"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-lmtpd"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-lucene"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-managesieved"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-mysql"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-pgsql"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-pop3d"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-sieve"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-solr"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "dovecot-sqlite"
        },
        {
            "binary_version": "1:2.2.22-1ubuntu2.14",
            "binary_name": "mail-stack-delivery"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42391.json"
Ubuntu:18.04:LTS
dovecot

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1:2.*
1:2.2.27-3ubuntu1
1:2.2.33.2-1ubuntu1
1:2.2.33.2-1ubuntu2
1:2.2.33.2-1ubuntu3
1:2.2.33.2-1ubuntu4
1:2.2.33.2-1ubuntu4.1
1:2.2.33.2-1ubuntu4.2
1:2.2.33.2-1ubuntu4.3
1:2.2.33.2-1ubuntu4.4
1:2.2.33.2-1ubuntu4.5
1:2.2.33.2-1ubuntu4.6
1:2.2.33.2-1ubuntu4.7
1:2.2.33.2-1ubuntu4.8

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-core"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-gssapi"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-imapd"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-ldap"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-lmtpd"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-managesieved"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-mysql"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-pgsql"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-pop3d"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-sieve"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-solr"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "dovecot-sqlite"
        },
        {
            "binary_version": "1:2.2.33.2-1ubuntu4.8",
            "binary_name": "mail-stack-delivery"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42391.json"
Ubuntu:20.04:LTS
dovecot

Package

Name
dovecot
Purl
pkg:deb/ubuntu/dovecot?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_version": "1:2.3.7.2-1ubuntu3.7",
            "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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42391.json"
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

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
1:2.3.16+dfsg1-3ubuntu2.9

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1:2.3.16+dfsg1-3ubuntu2.9",
            "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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42391.json"
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

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
1:2.3.21+dfsg1-2ubuntu6.5

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1:2.3.21+dfsg1-2ubuntu6.5",
            "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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42391.json"
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

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
1:2.4.2+dfsg1-3ubuntu2.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1:2.4.2+dfsg1-3ubuntu2.1",
            "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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42391.json"
Ubuntu:Pro:14.04:LTS
dovecot

Package

Name
dovecot
Purl
pkg:deb/ubuntu/dovecot?arch=source&distro=esm-infra-legacy%2Ftrusty

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1:2.*
1:2.1.7-7ubuntu3
1:2.2.9-1ubuntu1
1:2.2.9-1ubuntu2
1:2.2.9-1ubuntu2.1
1:2.2.9-1ubuntu2.3
1:2.2.9-1ubuntu2.4
1:2.2.9-1ubuntu2.5
1:2.2.9-1ubuntu2.6
1:2.2.9-1ubuntu2.6+esm1
1:2.2.9-1ubuntu2.6+esm2
1:2.2.9-1ubuntu2.6+esm3
1:2.2.9-1ubuntu2.6+esm4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-core"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-gssapi"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-imapd"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-ldap"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-lmtpd"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-managesieved"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-mysql"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-pgsql"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-pop3d"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-sieve"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-solr"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "dovecot-sqlite"
        },
        {
            "binary_version": "1:2.2.9-1ubuntu2.6+esm4",
            "binary_name": "mail-stack-delivery"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42391.json"