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.
CVE-2026-40194
This low-severity CVE scores 3.7 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 74% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 3.7
- EG Score
- 3.7(medium)
- EG Risk
- 33(Track)EG Risk 33/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity37% × 45%Exploitation40% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 25.8%
- KEV
- Not listed
Published
April 10, 2026
Last Modified
May 8, 2026
References (6)
- security-advisories@githubhttps://github.com/phpseclib/phpseclib/commit/ffe48b6b1b1af6963327f0a5330e3aa004a194ac
- security-advisories@githubhttps://github.com/phpseclib/phpseclib/releases/tag/1.0.28
- security-advisories@githubhttps://github.com/phpseclib/phpseclib/releases/tag/2.0.53
- security-advisories@githubhttps://github.com/phpseclib/phpseclib/releases/tag/3.0.51
- security-advisories@githubhttps://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx
- 134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx
Affected Packages
(1 across 1 ecosystem)
Packagist(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| phpseclib/phpseclib | 3.0.0 ... 3.0.9 (42 versions) | 3.0.51 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 35× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 03:11 UTCEG score recompute
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Frequently asked(5)
What is CVE-2026-40194?
When was CVE-2026-40194 disclosed?
Is CVE-2026-40194 actively exploited?
What is the CVSS score of CVE-2026-40194?
How do I remediate CVE-2026-40194?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-40194
Is Your Infrastructure Affected by CVE-2026-40194?
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