CVE-2026-40194 phpseclib has a variable-time HMAC comparison in SSH2::get_binary_packet() using != instead of hash_equals()

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::getbinarypacket 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,...