CVEvulnerability
CVE-2026-56123
9.2 CRITICAL
Official page ↗
- Status
- Analyzed
- Published
- 2026-06-25
- Last modified
- 2026-06-26
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 9.2 CRITICAL — 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVSS 3.1 ([email protected])
- 8.1 HIGH — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CVSS 3.1 ([email protected])
- 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weaknesses
- CWE-122
Description
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 bytes_to_read 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.
Affected configurations
• dest-unreach socat (>= 1.8.0.0 < 1.8.1.2)
Related
Weakness · CWE (1)
- CWE-122 Heap-based Buffer Overflow weakness
References
- http://www.dest-unreach.org/socat/CHANGES Release Notes
- https://www.vulncheck.com/advisories/socat-heap-buffer-overflow-via-socks5-reply-parser Third Party Advisory