Improper Handling of Case Sensitivity Affecting fast-uri package, versions <2.4.7>=3.0.0 <3.1.8>=4.0.0 <4.1.5
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.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-JS-FASTURI-19846649
- published16 Sept 2026
- disclosed15 Sept 2026
- creditfg0x0
Introduced: 15 Sep 2026
NewCVE-2026-86472 (opens in a new tab)How to fix?
Upgrade fast-uri to version 2.4.7, 3.1.8, 4.1.5 or higher.
Overview
fast-uri is a Dependency-free RFC 3986 URI toolbox
Affected versions of this package are vulnerable to Improper Handling of Case Sensitivity due to inconsistent normalization in the host component. An attacker can gain unauthorized access to restricted resources or services by submitting a specially crafted URI containing percent-encoded uppercase characters, which may bypass host allowlists or denylists in applications relying on case-sensitive host validation.