CVE-2026-40194

LOW3.7EPSS 0.01%

phpseclib has a variable-time HMAC comparison in SSH2::get_binary_packet() using != instead of hash_equals()

發布日:2026/4/10修改日:2026/5/27

描述

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.

受影響套件(4)

CVSS 分數

來源版本嚴重程度向量
osvCVSS 3.1LOW3.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

參考連結(8)