CVE-2026-56123— socat 1.8.0.0 - 1.8.1.1 Heap Buffer Overflow via SOCKS5 Reply Parser
Possible ATT&CK Techniques 1AI
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I. Basic Information for CVE-2026-56123
Vulnerability Information
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Vulnerability Title
socat 1.8.0.0 - 1.8.1.1 Heap Buffer Overflow via SOCKS5 Reply Parser
Source: NVD (National Vulnerability Database)
Vulnerability 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.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
堆缓冲区溢出
Source: NVD (National Vulnerability Database)
Vulnerability Title
socat 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
socat是socat个人开发者开源的一个中继器,用于在两个独立的数据之间进行双向数据传输渠道。 socat 1.8.1.1及之前版本和1.8.0.0版本存在缓冲区错误漏洞，该漏洞源于DOMAINNAME回复解析器中符号扩展缺陷导致的堆缓冲区溢出，允许恶意SOCKS5代理服务器利用有符号字符字段读取域名长度字节导致负的bytes_to_read值转换为size_t，造成对262字节回复缓冲区的无界堆写入。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-56123
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Vendor Advisories for CVE-2026-56123 (1)
IV. Related Vulnerabilities
Same product: socat
V. Comments for CVE-2026-56123
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