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

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

https://cvefeed.io/rssfeed/latest.atom / Sat, 04/11/2026 - 00:42
CVE ID :CVE-2026-40194
Published : April 10, 2026, 8:24 p.m. | 45 minutes ago
Description :phpseclib is a PHP secure communications library. 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.
Severity: 0.0 | NA
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Kenya Education Network CERT(KENET-CERT) is a Cybersecurity Emergency Response Team and Co-ordination Center operated by the National Research and Education Network of Kenya. KENET-CERT coordination center promotes awareness on cybersecurity incidences as well as coordinates and assists member institutions in responding effectively to cyber security threats and incidences. KENET-CERT works closely with Kenya's National CIRT coordination center (CIRT/CC) as a sector CIRT for the academic institutions. KENET promotes use of ICT in Teaching, Learning and Research in Higher Education Institutions in Kenya. KENET aims to interconnect all the Universities, Tertiary and Research Institutions in Kenya by setting up a cost effective and sustainable private network with high speed access to the global Internet. KENET also facilitates electronic communication among students and faculties in member institutions, share learning and teaching resources by collaboration in Research and Development of Educational content.