UBUNTU-CVE-2026-56123

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Source
https://ubuntu.com/security/CVE-2026-56123
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56123.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-56123
Upstream
  • CVE-2026-56123
Downstream
Related
Published
2026-06-25T17:17:00Z
Modified
2026-07-06T20:30:34.894825014Z
Severity
  • 8.1 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • 9.2 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

socat versions 1.8.0.0 through 1.8.1.1 contain a heap-based buffer overflow vulnerability that allows a malicious SOCKS5 proxy server to overwrite adjacent heap memory by exploiting a sign-extension flaw in the DOMAINNAME reply parser. During connection setup, the domain name length byte is read through a signed char field causing a negative bytestoread value that is implicitly converted to size_t, resulting in an unbounded heap write into the 262-byte reply buffer with attacker-controlled size and content.

References

Affected packages

Ubuntu:24.04:LTS / socat

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.8.0.0-4ubuntu0.1

Affected versions

1.*
1.7.4.4-2
1.8.0.0-4
1.8.0.0-4build1
1.8.0.0-4build2
1.8.0.0-4build3

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "socat",
            "binary_version": "1.8.0.0-4ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56123.json"

Ubuntu:25.10 / socat

Package

Name
socat
Purl
pkg:deb/ubuntu/socat?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.8.0.2-1
1.8.0.3-1
1.8.0.3-1build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "socat",
            "binary_version": "1.8.0.3-1build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56123.json"

Ubuntu:26.04:LTS / socat

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.8.1.1-1ubuntu0.1

Affected versions

1.*
1.8.0.3-1build1
1.8.1.0-1
1.8.1.0-2
1.8.1.1-1

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "socat",
            "binary_version": "1.8.1.1-1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56123.json"