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GHSA-F83F-XPX7-FFPW

Vulnerability from github – Published: 2025-12-05 18:18 – Updated: 2025-12-05 18:18
VLAI
Summary
Fulcio allocates excessive memory during token parsing
Details

Function identity.extractIssuerURL currently splits (via a call to strings.Split) its argument (which is untrusted data) on periods.

As a result, in the face of a malicious request with an (invalid) OIDC identity token in the payload containing many period characters, a call to extractIssuerURL incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. Relevant weakness: CWE-405: Asymmetric Resource Consumption (Amplification)

Details See identity.extractIssuerURL

Impact Excessive memory allocation

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.8.2"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/sigstore/fulcio"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.8.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-66506"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-405"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-12-05T18:18:26Z",
    "nvd_published_at": "2025-12-04T22:15:49Z",
    "severity": "HIGH"
  },
  "details": "Function [identity.extractIssuerURL](https://github.com/sigstore/fulcio/blob/main/pkg/identity/issuerpool.go#L44-L45) currently splits (via a call to [strings.Split](https://pkg.go.dev/strings#Split)) its argument (which is untrusted data) on periods.\n\nAs a result, in the face of a malicious request with an (invalid) OIDC identity token in the payload containing many period characters, a call to `extractIssuerURL` incurs allocations to the tune of O(n) bytes (where n stands for the length of the function\u0027s argument), with a constant factor of about 16. Relevant weakness: [CWE-405: Asymmetric Resource Consumption (Amplification)](https://cwe.mitre.org/data/definitions/405.html)\n\nDetails\nSee [identity.extractIssuerURL](https://github.com/sigstore/fulcio/blob/main/pkg/identity/issuerpool.go#L44-L45)\n\nImpact\nExcessive memory allocation",
  "id": "GHSA-f83f-xpx7-ffpw",
  "modified": "2025-12-05T18:18:26Z",
  "published": "2025-12-05T18:18:26Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sigstore/fulcio/security/advisories/GHSA-f83f-xpx7-ffpw"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66506"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sigstore/fulcio/commit/765a0e57608b9ef390e1eeeea8595b9054c63a5a"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sigstore/fulcio"
    }
  ],
  "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"
    }
  ],
  "summary": "Fulcio allocates excessive memory during token parsing"
}



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