{"id":"DEBIAN-CVE-2026-56123","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 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.","modified":"2026-09-14T17:03:20.795008284Z","published":"2026-06-25T17:17:01.967Z","upstream":["CVE-2026-56123"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-56123"}],"affected":[{"package":{"name":"socat","ecosystem":"Debian:13","purl":"pkg:deb/debian/socat?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.0.3-1+deb13u1"}]}],"versions":["1.8.0.3-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-56123.json"}},{"package":{"name":"socat","ecosystem":"Debian:14","purl":"pkg:deb/debian/socat?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.1.3-1"}]}],"versions":["1.8.0.3-1","1.8.1.0-1","1.8.1.0-2","1.8.1.1-1","1.8.1.1-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-56123.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}