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CVE-2026-40194

LOW

3.7

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.

CVE Details

CVSS v3.1 Score3.7

SeverityLOW

CVSS VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack VectorNETWORK

ComplexityHIGH

Privileges RequiredNONE

User InteractionNONE

Published4/10/2026

Last Modified4/13/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-208

References

https://github.com/phpseclib/phpseclib/commit/ffe48b6b1b1af6963327f0a5330e3aa004a194ac(security-advisories@github.com)

https://github.com/phpseclib/phpseclib/releases/tag/1.0.28(security-advisories@github.com)

https://github.com/phpseclib/phpseclib/releases/tag/2.0.53(security-advisories@github.com)

https://github.com/phpseclib/phpseclib/releases/tag/3.0.51(security-advisories@github.com)

https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx(security-advisories@github.com)

https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx(134c704f-9b21-4f2e-91b3-4a467353bcc0)

IOC Correlations

No correlations recorded

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