CVE-2026-40194
3.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| phpseclib | phpseclib | >= 0.1.1, < 1.0.28 | affected |
| phpseclib | phpseclib | >= 2.0.0, < 2.0.53 | affected |
| phpseclib | phpseclib | >= 3.0.0, < 3.0.51 | affected |
Weaknesses
- CWE-208: CWE-208: Observable Timing Discrepancy
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: poc
- Automatable: no
- Technical Impact: partial
Additional References
References
- https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx
- https://github.com/phpseclib/phpseclib/commit/ffe48b6b1b1af6963327f0a5330e3aa004a194ac
- https://github.com/phpseclib/phpseclib/releases/tag/1.0.28
- https://github.com/phpseclib/phpseclib/releases/tag/2.0.53
- https://github.com/phpseclib/phpseclib/releases/tag/3.0.51
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