UBUNTU-CVE-2026-19773

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Source
https://ubuntu.com/security/CVE-2026-19773
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19773.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-19773
Upstream
Downstream
Related
Published
2026-09-15T19:17:00Z
Modified
2026-10-08T12:53:39Z
Severity
  • 9.8 (Critical) CVSS_V3 - CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

libwebsockets HTTP/2 HPACK Path Header Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of libwebsockets. Authentication is not required to exploit this vulnerability. The specific flaw exists within the parsing of HTTP/2 HPACK path header. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-31036.

References

Affected packages

Ubuntu:Pro:16.04:LTS
libwebsockets

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
1.7.1-1ubuntu0.1~esm1

Affected versions

1.*
1.2.2-1
1.6.0-3
1.6.0-4
1.6.0-5
1.6.1-1
1.7.0-1ubuntu1
1.7.0-2
1.7.1-1

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libwebsockets-test-server",
            "binary_version": "1.7.1-1ubuntu0.1~esm1"
        },
        {
            "binary_name": "libwebsockets-test-server-common",
            "binary_version": "1.7.1-1ubuntu0.1~esm1"
        },
        {
            "binary_name": "libwebsockets7",
            "binary_version": "1.7.1-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19773.json"
Ubuntu:Pro:18.04:LTS
libwebsockets

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.0.3-3ubuntu0.1~esm1

Affected versions

2.*
2.0.3-3
2.0.3-3build1

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libwebsockets-test-server",
            "binary_version": "2.0.3-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "libwebsockets-test-server-common",
            "binary_version": "2.0.3-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "libwebsockets8",
            "binary_version": "2.0.3-3ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19773.json"
Ubuntu:Pro:20.04:LTS
libwebsockets

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.2.1-3ubuntu0.1~esm3

Affected versions

2.*
2.0.3-3build1
3.*
3.2.1-3
3.2.1-3ubuntu0.1~esm1
3.2.1-3ubuntu0.1~esm2

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libwebsockets-test-server",
            "binary_version": "3.2.1-3ubuntu0.1~esm3"
        },
        {
            "binary_name": "libwebsockets-test-server-common",
            "binary_version": "3.2.1-3ubuntu0.1~esm3"
        },
        {
            "binary_name": "libwebsockets15",
            "binary_version": "3.2.1-3ubuntu0.1~esm3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19773.json"
Ubuntu:Pro:22.04:LTS
libwebsockets

Package

Name
libwebsockets
Purl
pkg:deb/ubuntu/libwebsockets?arch=source&distro=esm-apps%2Fjammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
4.0.20-2ubuntu1.1+esm2

Affected versions

4.*
4.0.20-2
4.0.20-2ubuntu1
4.0.20-2ubuntu1.1
4.0.20-2ubuntu1.1+esm1

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libwebsockets-test-server",
            "binary_version": "4.0.20-2ubuntu1.1+esm2"
        },
        {
            "binary_name": "libwebsockets-test-server-common",
            "binary_version": "4.0.20-2ubuntu1.1+esm2"
        },
        {
            "binary_name": "libwebsockets16",
            "binary_version": "4.0.20-2ubuntu1.1+esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19773.json"
Ubuntu:Pro:24.04:LTS
libwebsockets

Package

Name
libwebsockets
Purl
pkg:deb/ubuntu/libwebsockets?arch=source&distro=esm-apps%2Fnoble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
4.3.3-1.1ubuntu0.1~esm3

Affected versions

4.*
4.3.2-4
4.3.3-1
4.3.3-1.1build1
4.3.3-1.1build2
4.3.3-1.1build3
4.3.3-1.1ubuntu0.1~esm1
4.3.3-1.1ubuntu0.1~esm2

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libwebsockets-evlib-ev",
            "binary_version": "4.3.3-1.1ubuntu0.1~esm3"
        },
        {
            "binary_name": "libwebsockets-evlib-glib",
            "binary_version": "4.3.3-1.1ubuntu0.1~esm3"
        },
        {
            "binary_name": "libwebsockets-evlib-uv",
            "binary_version": "4.3.3-1.1ubuntu0.1~esm3"
        },
        {
            "binary_name": "libwebsockets-test-server",
            "binary_version": "4.3.3-1.1ubuntu0.1~esm3"
        },
        {
            "binary_name": "libwebsockets-test-server-common",
            "binary_version": "4.3.3-1.1ubuntu0.1~esm3"
        },
        {
            "binary_name": "libwebsockets19t64",
            "binary_version": "4.3.3-1.1ubuntu0.1~esm3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19773.json"
Ubuntu:Pro:26.04:LTS
libwebsockets

Package

Name
libwebsockets
Purl
pkg:deb/ubuntu/libwebsockets?arch=source&distro=esm-apps%2Fresolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
4.3.5-3ubuntu1.2+esm1

Affected versions

4.*
4.3.5-1
4.3.5-3
4.3.5-3ubuntu1
4.3.5-3ubuntu1.1

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "libwebsockets-evlib-ev",
            "binary_version": "4.3.5-3ubuntu1.2+esm1"
        },
        {
            "binary_name": "libwebsockets-evlib-glib",
            "binary_version": "4.3.5-3ubuntu1.2+esm1"
        },
        {
            "binary_name": "libwebsockets-evlib-uv",
            "binary_version": "4.3.5-3ubuntu1.2+esm1"
        },
        {
            "binary_name": "libwebsockets-test-server",
            "binary_version": "4.3.5-3ubuntu1.2+esm1"
        },
        {
            "binary_name": "libwebsockets-test-server-common",
            "binary_version": "4.3.5-3ubuntu1.2+esm1"
        },
        {
            "binary_name": "libwebsockets19t64",
            "binary_version": "4.3.5-3ubuntu1.2+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19773.json"