GHSA-8QWJ-4JXW-M8JW

Vulnerability from github – Published: 2026-03-23 06:30 – Updated: 2026-03-30 19:30
VLAI
Summary
jsrsasign: Negative Exponent Handling Leads to Signature Verification Bypass
Details

Versions of the package jsrsasign before 11.1.1 are vulnerable to Incorrect Conversion between Numeric Types due to handling negative exponents in ext/jsbn2.js. An attacker can force the computation of incorrect modular inverses and break signature verification by calling modPow with a negative exponent.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "jsrsasign"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "11.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-4602"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-681"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-30T19:30:01Z",
    "nvd_published_at": "2026-03-23T06:16:22Z",
    "severity": "HIGH"
  },
  "details": "Versions of the package jsrsasign before 11.1.1 are vulnerable to Incorrect Conversion between Numeric Types due to handling negative exponents in ext/jsbn2.js. An attacker can force the computation of incorrect modular inverses and break signature verification by calling modPow with a negative exponent.",
  "id": "GHSA-8qwj-4jxw-m8jw",
  "modified": "2026-03-30T19:30:01Z",
  "published": "2026-03-23T06:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4602"
    },
    {
      "type": "WEB",
      "url": "https://github.com/kjur/jsrsasign/pull/650"
    },
    {
      "type": "WEB",
      "url": "https://github.com/kjur/jsrsasign/commit/5ea1c32bb2aa894b4bd29849839afe4f98728195"
    },
    {
      "type": "WEB",
      "url": "https://gist.github.com/Kr0emer/7ecd2be7d17419e4677315ef3758faf5"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/kjur/jsrsasign"
    },
    {
      "type": "WEB",
      "url": "https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15371175"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "jsrsasign: Negative Exponent Handling Leads to Signature Verification Bypass"
}


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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.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.