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1 vulnerability by socat
CVE-2026-56123 (GCVE-0-2026-56123)
Vulnerability from cvelistv5 – Published: 2026-06-25 15:43 – Updated: 2026-07-14 21:34 X_Open Source
VLAI
EPSS
VEX
Title
socat 1.8.0.0 - 1.8.1.1 Heap Buffer Overflow via SOCKS5 Reply Parser
Summary
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.
Severity
8.1 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-26 02:03 UTC
CWE
- CWE-122 - Heap-based Buffer Overflow
Assigner
VulnCheck
CNA
References
2 references
| URL | Tags |
|---|---|
| http://www.dest-unreach.org/socat/CHANGES | release-notespatch |
| https://www.vulncheck.com/advisories/socat-heap-b… | third-party-advisory |
Impacted products
Date Public
2026-06-25 00:00
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