{"id":"CVE-2026-40194","aliases":["GHSA-r854-jrxh-36qx"],"url":"https://o3.security/vulnerability/CVE-2026-40194","summary":"phpseclib has a variable-time HMAC comparison in SSH2::get_binary_packet() using != instead of hash_equals()","details":"phpseclib is a PHP secure communications library. Starting in 0.1.1 and prior to 3.0.51, 2.0.53, and 1.0.28, phpseclib\\Net\\SSH2::get_binary_packet() uses PHP's != operator to compare a received SSH packet HMAC against the locally computed HMAC. != on equal-length binary strings in PHP uses memcmp(), which short-circuits on the first differing byte. This is a real variable-time comparison (CWE-208), proven by scaling benchmarks. This vulnerability is fixed in 3.0.51, 2.0.53, and 1.0.28.","published":"2026-04-10T20:24:06.696Z","modified":"2026-08-07T11:49:50.763523032Z","cvss":{"score":3.7,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"phpseclib/phpseclib","fixedVersion":"1.0.28"},{"ecosystem":"Packagist","name":"phpseclib/phpseclib","fixedVersion":"2.0.53"},{"ecosystem":"Packagist","name":"phpseclib/phpseclib","fixedVersion":"3.0.51"}],"fix":{"url":"https://github.com/phpseclib/phpseclib/commit/ffe48b6b1b1af6963327f0a5330e3aa004a194ac","label":"phpseclib/phpseclib@ffe48b6"},"references":[{"type":"WEB","url":"https://github.com/phpseclib/phpseclib/releases/tag/1.0.28"},{"type":"WEB","url":"https://github.com/phpseclib/phpseclib/releases/tag/2.0.53"},{"type":"WEB","url":"https://github.com/phpseclib/phpseclib/releases/tag/3.0.51"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40194.json"},{"type":"ADVISORY","url":"https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40194"},{"type":"FIX","url":"https://github.com/phpseclib/phpseclib/commit/ffe48b6b1b1af6963327f0a5330e3aa004a194ac"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:49:50.763523032Z"}}