CVE-2026-40194

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.

CVSS v3 3.7 LOW

3.7^/10

CVSS v3 : LOW

Vector :

Exploitability : 2.2 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/phpseclib/phpseclib/commit/ffe48b6b1b1af6963327f0a5330e3aa004a194ac	Patch
https://github.com/phpseclib/phpseclib/releases/tag/1.0.28	Release Notes
https://github.com/phpseclib/phpseclib/releases/tag/2.0.53	Release Notes
https://github.com/phpseclib/phpseclib/releases/tag/3.0.51	Release Notes
https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx	Vendor Advisory
https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:phpseclib:phpseclib::::::::
	cpe:2.3:a:phpseclib:phpseclib::::::::
	cpe:2.3:a:phpseclib:phpseclib::::::::

History

No history.

Information

Published : 2026-04-10 21:16

Updated : 2026-06-17 10:44

NVD link : CVE-2026-40194

Mitre link : CVE-2026-40194

CVE.ORG link : CVE-2026-40194

JSON object : View

Products Affected

phpseclib

phpseclib

CWE

CWE-208

Observable Timing Discrepancy

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