UBUNTU-CVE-2026-63379

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Source
https://ubuntu.com/security/CVE-2026-63379
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63379.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-63379
Upstream
Published
2026-08-20T18:16:00Z
Modified
2026-09-02T19:35:54Z
Severity
  • 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/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 processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ and a temporary trailer header list. An unauthenticated remote attacker can place security-sensitive fields in trailers so that an upstream proxy and the libevent application interpret different effective headers, enabling header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning. The fix parses trailers into a temporary header list and discards them instead of merging them into req->input_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

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

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 

{
    "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-2026-63379.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

Affected versions

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

Ecosystem specific 

{
    "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-2026-63379.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

Affected versions

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

Ecosystem specific 

{
    "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-2026-63379.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

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 

{
    "binaries": [
        {
            "binary_name": "libevent-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
        },
        {
            "binary_name": "libevent-core-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
        },
        {
            "binary_name": "libevent-extra-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
        },
        {
            "binary_name": "libevent-openssl-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
        },
        {
            "binary_name": "libevent-pthreads-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63379.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

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 

{
    "binaries": [
        {
            "binary_name": "libevent-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
        },
        {
            "binary_name": "libevent-core-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
        },
        {
            "binary_name": "libevent-extra-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
        },
        {
            "binary_name": "libevent-openssl-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
        },
        {
            "binary_name": "libevent-pthreads-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-63379.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

Affected versions

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

Ecosystem specific 

{
    "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-2026-63379.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

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 

{
    "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-2026-63379.json"