Time-of-check Time-of-use (TOCTOU) Race Condition Affecting craftcms/cms package, versions >=3.5.0, <4.16.19>=5.0.0-RC1, <5.8.23
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published24 Feb 2026
- disclosed23 Feb 2026
- creditRaj Chowdhury, rlarabee
Introduced: 23 Feb 2026
CVE-2026-27127 (opens in a new tab)How to fix?
Upgrade craftcms/cms to version 4.16.19, 5.8.23 or higher.
Overview
craftcms/cms is a content management system.
Affected versions of this package are vulnerable to Time-of-check Time-of-use (TOCTOU) Race Condition in the validateHostname function. An attacker can access internal cloud metadata endpoints and retrieve sensitive credentials by exploiting a race condition between DNS resolution during validation and the actual HTTP request, using DNS rebinding techniques.
Note: This is a bypass of the security fix for CVE-2025-68437.