UBUNTU-CVE-2026-63381

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Source
https://ubuntu.com/security/CVE-2026-63381
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63381.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-63381
Upstream
Downstream
Related
Published
2026-08-21T00:00:00Z
Modified
2026-09-02T19:35:54Z
Severity
  • 5.8 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains frees the initial empty chain without resetting outbuf->first, outbuf->last, or outbuf->last_with_datap, and APPEND_CHAIN_MULTICAST subsequently dereferences the dangling chain pointer. A caller that can drive this buffer state can cause memory corruption or a process crash. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

References

Affected packages

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~esm1

Affected versions

2.*
2.1.8-stable-4
2.1.8-stable-4build1

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~esm1"
        },
        {
            "binary_name": "libevent-core-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
        },
        {
            "binary_name": "libevent-extra-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
        },
        {
            "binary_name": "libevent-openssl-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
        },
        {
            "binary_name": "libevent-pthreads-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63381.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~esm1

Affected versions

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

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~esm1"
        },
        {
            "binary_name": "libevent-core-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
        },
        {
            "binary_name": "libevent-extra-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
        },
        {
            "binary_name": "libevent-openssl-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
        },
        {
            "binary_name": "libevent-pthreads-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63381.json"

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-1ubuntu0.1

Affected versions

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

Ecosystem specific 

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

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63381.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-9ubuntu2.1

Affected versions

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

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "libevent-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
        },
        {
            "binary_name": "libevent-core-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
        },
        {
            "binary_name": "libevent-extra-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
        },
        {
            "binary_name": "libevent-openssl-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
        },
        {
            "binary_name": "libevent-pthreads-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63381.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-10ubuntu0.1

Affected versions

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

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "libevent-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
        },
        {
            "binary_name": "libevent-core-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
        },
        {
            "binary_name": "libevent-extra-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
        },
        {
            "binary_name": "libevent-openssl-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
        },
        {
            "binary_name": "libevent-pthreads-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63381.json"