USN-8840-1

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Source
https://ubuntu.com/security/notices/USN-8840-1
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8840-1.json
JSON Data
https://api.osv.dev/v1/vulns/USN-8840-1
Upstream
CVE (2)
Related
UBUNTU (2)
Published
2026-09-28T20:05:19Z
Modified
2026-09-29T23:56:46Z
Summary
libevent vulnerabilities
Details

Michał Majchrowicz and Marcin Wyczechowski discovered that libevent incorrectly handled certain DNS responses. A remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code. (CVE-2026-63387)

It was discovered that libevent incorrectly handled certain connections. A local attacker could possibly use this issue to cause a denial of service or execute arbitrary code. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-63388)

References

Affected packages

Ubuntu:22.04:LTS
libevent

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.1.12-stable-1ubuntu0.2

Affected versions

2.*
2.1.12-stable-1
2.1.12-stable-1build1
2.1.12-stable-1build2
2.1.12-stable-1build3
2.1.12-stable-1ubuntu0.1

Ecosystem specific 

{
    "availability":  "No subscription required",
    "binaries":  [
        {
            "binary_name":  "libevent-2.1-7",
            "binary_version":  "2.1.12-stable-1ubuntu0.2"
        },
        {
            "binary_name":  "libevent-core-2.1-7",
            "binary_version":  "2.1.12-stable-1ubuntu0.2"
        },
        {
            "binary_name":  "libevent-extra-2.1-7",
            "binary_version":  "2.1.12-stable-1ubuntu0.2"
        },
        {
            "binary_name":  "libevent-openssl-2.1-7",
            "binary_version":  "2.1.12-stable-1ubuntu0.2"
        },
        {
            "binary_name":  "libevent-pthreads-2.1-7",
            "binary_version":  "2.1.12-stable-1ubuntu0.2"
        }
    ]
}

Database specific

cves_map 
{
    "cves":  [
        {
            "id":  "CVE-2026-63388",
            "severity":  [
                {
                    "score":  "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                    "type":  "CVSS_V3"
                },
                {
                    "score":  "medium",
                    "type":  "Ubuntu"
                }
            ]
        }
    ],
    "ecosystem":  "Ubuntu:22.04:LTS"
}
source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8840-1.json"
Ubuntu:24.04:LTS
libevent

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.1.12-stable-9ubuntu2.2

Affected versions

2.*
2.1.12-stable-9
2.1.12-stable-9ubuntu2
2.1.12-stable-9ubuntu2.1

Ecosystem specific 

{
    "availability":  "No subscription required",
    "binaries":  [
        {
            "binary_name":  "libevent-2.1-7t64",
            "binary_version":  "2.1.12-stable-9ubuntu2.2"
        },
        {
            "binary_name":  "libevent-core-2.1-7t64",
            "binary_version":  "2.1.12-stable-9ubuntu2.2"
        },
        {
            "binary_name":  "libevent-extra-2.1-7t64",
            "binary_version":  "2.1.12-stable-9ubuntu2.2"
        },
        {
            "binary_name":  "libevent-openssl-2.1-7t64",
            "binary_version":  "2.1.12-stable-9ubuntu2.2"
        },
        {
            "binary_name":  "libevent-pthreads-2.1-7t64",
            "binary_version":  "2.1.12-stable-9ubuntu2.2"
        }
    ]
}

Database specific

cves_map 
{
    "cves":  [
        {
            "id":  "CVE-2026-63388",
            "severity":  [
                {
                    "score":  "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                    "type":  "CVSS_V3"
                },
                {
                    "score":  "medium",
                    "type":  "Ubuntu"
                }
            ]
        }
    ],
    "ecosystem":  "Ubuntu:24.04:LTS"
}
source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8840-1.json"
Ubuntu:26.04:LTS
libevent

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.1.12-stable-10ubuntu0.2

Affected versions

2.*
2.1.12-stable-10build1
2.1.12-stable-10build2
2.1.12-stable-10ubuntu0.1

Ecosystem specific 

{
    "availability":  "No subscription required",
    "binaries":  [
        {
            "binary_name":  "libevent-2.1-7t64",
            "binary_version":  "2.1.12-stable-10ubuntu0.2"
        },
        {
            "binary_name":  "libevent-core-2.1-7t64",
            "binary_version":  "2.1.12-stable-10ubuntu0.2"
        },
        {
            "binary_name":  "libevent-extra-2.1-7t64",
            "binary_version":  "2.1.12-stable-10ubuntu0.2"
        },
        {
            "binary_name":  "libevent-openssl-2.1-7t64",
            "binary_version":  "2.1.12-stable-10ubuntu0.2"
        },
        {
            "binary_name":  "libevent-pthreads-2.1-7t64",
            "binary_version":  "2.1.12-stable-10ubuntu0.2"
        }
    ]
}

Database specific

cves_map 
{
    "cves":  [
        {
            "id":  "CVE-2026-63387",
            "severity":  [
                {
                    "score":  "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H",
                    "type":  "CVSS_V3"
                },
                {
                    "score":  "medium",
                    "type":  "Ubuntu"
                }
            ]
        },
        {
            "id":  "CVE-2026-63388",
            "severity":  [
                {
                    "score":  "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                    "type":  "CVSS_V3"
                },
                {
                    "score":  "medium",
                    "type":  "Ubuntu"
                }
            ]
        }
    ],
    "ecosystem":  "Ubuntu:26.04:LTS"
}
source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8840-1.json"
Ubuntu:Pro:14.04:LTS
libevent

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.0.21-stable-1ubuntu1.14.04.2+esm2

Affected versions

2.*
2.0.21-stable-1
2.0.21-stable-1ubuntu1
2.0.21-stable-1ubuntu1.14.04.1
2.0.21-stable-1ubuntu1.14.04.2
2.0.21-stable-1ubuntu1.14.04.2+esm1

Ecosystem specific 

{
    "availability":  "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
    "binaries":  [
        {
            "binary_name":  "libevent-2.0-5",
            "binary_version":  "2.0.21-stable-1ubuntu1.14.04.2+esm2"
        },
        {
            "binary_name":  "libevent-core-2.0-5",
            "binary_version":  "2.0.21-stable-1ubuntu1.14.04.2+esm2"
        },
        {
            "binary_name":  "libevent-extra-2.0-5",
            "binary_version":  "2.0.21-stable-1ubuntu1.14.04.2+esm2"
        },
        {
            "binary_name":  "libevent-openssl-2.0-5",
            "binary_version":  "2.0.21-stable-1ubuntu1.14.04.2+esm2"
        },
        {
            "binary_name":  "libevent-pthreads-2.0-5",
            "binary_version":  "2.0.21-stable-1ubuntu1.14.04.2+esm2"
        }
    ]
}

Database specific

cves_map 
{
    "cves":  [],
    "ecosystem":  "Ubuntu:Pro:14.04:LTS"
}
source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8840-1.json"
Ubuntu:Pro:16.04:LTS
libevent

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.0.21-stable-2ubuntu0.16.04.1+esm2

Affected versions

2.*
2.0.21-stable-2
2.0.21-stable-2ubuntu0.16.04.1
2.0.21-stable-2ubuntu0.16.04.1+esm1

Ecosystem specific 

{
    "availability":  "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
    "binaries":  [
        {
            "binary_name":  "libevent-2.0-5",
            "binary_version":  "2.0.21-stable-2ubuntu0.16.04.1+esm2"
        },
        {
            "binary_name":  "libevent-core-2.0-5",
            "binary_version":  "2.0.21-stable-2ubuntu0.16.04.1+esm2"
        },
        {
            "binary_name":  "libevent-extra-2.0-5",
            "binary_version":  "2.0.21-stable-2ubuntu0.16.04.1+esm2"
        },
        {
            "binary_name":  "libevent-openssl-2.0-5",
            "binary_version":  "2.0.21-stable-2ubuntu0.16.04.1+esm2"
        },
        {
            "binary_name":  "libevent-pthreads-2.0-5",
            "binary_version":  "2.0.21-stable-2ubuntu0.16.04.1+esm2"
        }
    ]
}

Database specific

cves_map 
{
    "cves":  [],
    "ecosystem":  "Ubuntu:Pro:16.04:LTS"
}
source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8840-1.json"
Ubuntu:Pro:18.04:LTS
libevent

Package

Name
libevent
Purl
pkg:deb/ubuntu/libevent?arch=source&distro=esm-infra%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.1.8-stable-4ubuntu0.1~esm2

Affected versions

2.*
2.1.8-stable-4
2.1.8-stable-4build1
2.1.8-stable-4ubuntu0.1~esm1

Ecosystem specific 

{
    "availability":  "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
    "binaries":  [
        {
            "binary_name":  "libevent-2.1-6",
            "binary_version":  "2.1.8-stable-4ubuntu0.1~esm2"
        },
        {
            "binary_name":  "libevent-core-2.1-6",
            "binary_version":  "2.1.8-stable-4ubuntu0.1~esm2"
        },
        {
            "binary_name":  "libevent-extra-2.1-6",
            "binary_version":  "2.1.8-stable-4ubuntu0.1~esm2"
        },
        {
            "binary_name":  "libevent-openssl-2.1-6",
            "binary_version":  "2.1.8-stable-4ubuntu0.1~esm2"
        },
        {
            "binary_name":  "libevent-pthreads-2.1-6",
            "binary_version":  "2.1.8-stable-4ubuntu0.1~esm2"
        }
    ]
}

Database specific

cves_map 
{
    "cves":  [
        {
            "id":  "CVE-2026-63388",
            "severity":  [
                {
                    "score":  "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                    "type":  "CVSS_V3"
                },
                {
                    "score":  "medium",
                    "type":  "Ubuntu"
                }
            ]
        }
    ],
    "ecosystem":  "Ubuntu:Pro:18.04:LTS"
}
source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8840-1.json"
Ubuntu:Pro:20.04:LTS
libevent

Package

Name
libevent
Purl
pkg:deb/ubuntu/libevent?arch=source&distro=esm-infra%2Ffocal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.1.11-stable-1ubuntu0.1~esm2

Affected versions

2.*
2.1.8-stable-4build1
2.1.11-stable-1~exp0
2.1.11-stable-1
2.1.11-stable-1ubuntu0.1~esm1

Ecosystem specific 

{
    "availability":  "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
    "binaries":  [
        {
            "binary_name":  "libevent-2.1-7",
            "binary_version":  "2.1.11-stable-1ubuntu0.1~esm2"
        },
        {
            "binary_name":  "libevent-core-2.1-7",
            "binary_version":  "2.1.11-stable-1ubuntu0.1~esm2"
        },
        {
            "binary_name":  "libevent-extra-2.1-7",
            "binary_version":  "2.1.11-stable-1ubuntu0.1~esm2"
        },
        {
            "binary_name":  "libevent-openssl-2.1-7",
            "binary_version":  "2.1.11-stable-1ubuntu0.1~esm2"
        },
        {
            "binary_name":  "libevent-pthreads-2.1-7",
            "binary_version":  "2.1.11-stable-1ubuntu0.1~esm2"
        }
    ]
}

Database specific

cves_map 
{
    "cves":  [
        {
            "id":  "CVE-2026-63388",
            "severity":  [
                {
                    "score":  "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                    "type":  "CVSS_V3"
                },
                {
                    "score":  "medium",
                    "type":  "Ubuntu"
                }
            ]
        }
    ],
    "ecosystem":  "Ubuntu:Pro:20.04:LTS"
}
source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8840-1.json"