GHSA-6FX5-5CW5-4897

Vulnerability from github – Published: 2026-02-23 22:16 – Updated: 2026-02-24 16:08
VLAI?
Summary
Craft CMS Race condition in Token Service potentially allows for token usage greater than the token limit
Details

A Time-of-Check-Time-of-Use (TOCTOU) race condition exists in Craft CMS’s token validation service for tokens that explicitly set a limited usage. The getTokenRoute() method reads a token’s usage count, checks if it’s within limits, then updates the database in separate non-atomic operations. By sending concurrent requests, an attacker can use a single-use impersonation token multiple times before the database update completes.

To make this work, an attacker needs to obtain a valid user account impersonation URL with a non-expired token via some other means and exploit a race condition while bypassing any rate-limiting rules in place.

For this to be a privilege escalation, the impersonation URL must include a token for a user account with more permissions than the current user.

References

https://github.com/craftcms/cms/commit/3e4afe18279951c024c64896aa2b93cda6d95fdf

Severity ?
6.9 (Medium)
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.16.18"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "craftcms/cms"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.5.0-RC1"
            },
            {
              "fixed": "4.16.19"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 5.8.22"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "craftcms/cms"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.0.0-RC1"
            },
            {
              "fixed": "5.8.23"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27128"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-367"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-23T22:16:22Z",
    "nvd_published_at": "2026-02-24T03:16:02Z",
    "severity": "MODERATE"
  },
  "details": "A Time-of-Check-Time-of-Use (TOCTOU) race condition exists in Craft CMS\u2019s token validation service for tokens that explicitly set a limited usage. The `getTokenRoute()` method reads a token\u2019s usage count, checks if it\u2019s within limits, then updates the database in separate non-atomic operations. By sending concurrent requests, an attacker can use a single-use impersonation token multiple times before the database update completes.\n\nTo make this work, an attacker needs to obtain a valid user account impersonation URL with a non-expired token via some other means and exploit a race condition while bypassing any rate-limiting rules in place.\n\nFor this to be a privilege escalation, the impersonation URL must include a token for a user account with more permissions than the current user.\n\n## References\n\nhttps://github.com/craftcms/cms/commit/3e4afe18279951c024c64896aa2b93cda6d95fdf",
  "id": "GHSA-6fx5-5cw5-4897",
  "modified": "2026-02-24T16:08:48Z",
  "published": "2026-02-23T22:16:22Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/craftcms/cms/security/advisories/GHSA-6fx5-5cw5-4897"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27128"
    },
    {
      "type": "WEB",
      "url": "https://github.com/craftcms/cms/commit/3e4afe18279951c024c64896aa2b93cda6d95fdf"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/craftcms/cms"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Craft CMS Race condition in Token Service potentially allows for token usage greater than the token limit"
}


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