phpseclib has a variable-time HMAC comparison in SSH2::get_binary_packet() using != instead of hash_equals() (phpseclib phpseclib)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.36 % · percentile 30 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
Description
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.
Weaknesses (CWE)
- CWE-208 — Observable Timing Discrepancy
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
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | LOW 3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N | GitHub_M |
| CVSS 3.1 | LOW 3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-r854-jrxh-36qx — phpseclib has a variable-time HMAC comparison in SSH2::get_binary_packet() using != instead of hash_equals()
European references
- ENISA EUVD · EUVD-2026-21597
- GCVE · GCVE-0-2026-40194
Affected configurations (NVD CPE)
cpe:2.3:a:phpseclib:phpseclib:*:*:*:*:*:*:*:*≤ 1.0.27cpe:2.3:a:phpseclib:phpseclib:*:*:*:*:*:*:*:*≥ 2.0.0 < 2.0.53cpe:2.3:a:phpseclib:phpseclib:*:*:*:*:*:*:*:*≥ 3.0.0 < 3.0.51
Affected products
| Product | Versions |
|---|---|
| phpseclib · phpseclib | affected >= 0.1.1, < 1.0.28 ; affected >= 2.0.0, < 2.0.53 ; affected >= 3.0.0, < 3.0.51 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |