fast-uri up to 3.1.1 normalize interpretation conflict

Summaryinfo

A vulnerability marked as problematic has been reported in fast-uri up to 3.1.1. This affects the function normalize. The manipulation leads to interpretation conflict. This vulnerability is uniquely identified as CVE-2026-6322. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in fast-uri up to 3.1.1. This issue affects the function normalize. The manipulation with an unknown input leads to a interpretation conflict vulnerability. Using CWE to declare the problem leads to CWE-436. Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state. Impacted is integrity. The summary by CVE is:

fast-uri normalize() decoded percent-encoded authority delimiters inside the host component and then re-emitted them as raw delimiters during serialization. A host that combined an allowed domain, an encoded at-sign, and a different domain was re-emitted with the at-sign as a raw userinfo separator, changing the URI's authority to the second domain. Applications that normalize untrusted URLs before host allowlist checks, redirect validation, or outbound request routing can be steered to a different authority than the input appeared to specify. Versions <= 3.1.1 are affected. Update to 3.1.2 or later.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-6322 since 04/14/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 312304 (Linux Distros Unpatched Vulnerability : CVE-2026-6322), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.1.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (312304). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Name

• fast-uri

Version

• 3.1.0
• 3.1.1

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

Discussion