FKIE_CVE-2026-40194

Vulnerability from fkie_nvd - Published: 2026-04-10 21:16 - Updated: 2026-04-21 19:19
Severity ?
3.7 (Low) - 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. 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.
References
security-advisories@github.comhttps://github.com/phpseclib/phpseclib/commit/ffe48b6b1b1af6963327f0a5330e3aa004a194acPatch
security-advisories@github.comhttps://github.com/phpseclib/phpseclib/releases/tag/1.0.28Release Notes
security-advisories@github.comhttps://github.com/phpseclib/phpseclib/releases/tag/2.0.53Release Notes
security-advisories@github.comhttps://github.com/phpseclib/phpseclib/releases/tag/3.0.51Release Notes
security-advisories@github.comhttps://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qxVendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qxVendor Advisory
Impacted products
Vendor Product Version
phpseclib phpseclib *
phpseclib phpseclib *
phpseclib phpseclib *
To clipboard 

{
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    {
      "nodes": [
        {
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              "criteria": "cpe:2.3:a:phpseclib:phpseclib:*:*:*:*:*:*:*:*",
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  "cveTags": [],
  "descriptions": [
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      "value": "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\u0027s != 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."
    }
  ],
  "id": "CVE-2026-40194",
  "lastModified": "2026-04-21T19:19:19.927",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 3.7,
          "baseSeverity": "LOW",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
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  "vulnStatus": "Analyzed",
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}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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