UBUNTU-CVE-2026-33263

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Source
https://ubuntu.com/security/CVE-2026-33263
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33263.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-33263
Upstream
  • CVE-2026-33263
Published
2026-08-28T00:00:00Z
Modified
2026-09-02T19:35:44Z
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

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.

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
0 Unknown 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_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",
            "binary_version":  "1:2.2.22-1ubuntu2.14"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33263.json"
Ubuntu:18.04:LTS
dovecot

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown 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_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",
            "binary_version":  "1:2.2.33.2-1ubuntu4.8"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33263.json"
Ubuntu:20.04:LTS
dovecot

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown 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-2026-33263.json"
Ubuntu:22.04:LTS
dovecot

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown 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_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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33263.json"
Ubuntu:24.04:LTS
dovecot

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown 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_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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33263.json"
Ubuntu:26.04:LTS
dovecot

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown 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_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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33263.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
0 Unknown 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_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",
            "binary_version":  "1:2.2.9-1ubuntu2.6+esm4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33263.json"