CVE-2026-76172

fast-uri is a URI parser for Node.js. During parsing it runs a legacy decoding pass over the scheme component and never re-escapes the result, and serialization writes the scheme back out verbatim, unlike the host component which is re-escaped. As a result an input whose scheme carries percent-encoded slashes parses as a scheme with no authority, so the parsed host and error are both undefined, yet resolving or normalizing that same input emits a network-path reference whose authority is attacker-chosen and re-parses to that host. An application that allowlists on the parsed host, or treats a reference with no authority as safe to resolve against its base, gets the opposite of what it checked, giving an off-site redirect, server-side request forgery, or address-policy bypass. The legacy decoder also expands non-standard escape forms, widening the issue past upstream filters, and control characters in the scheme can reach the output as raw carriage return and line feed. The affected versions are 2.3.1 up to but not including 2.4.5, 3.0.0 up to but not including 3.1.6, and 4.0.0 up to but not including 4.1.3. The issue is fixed in 2.4.5, 3.1.6, and 4.1.3, which reject a scheme that is not valid after decoding. Users should upgrade to a patched version.
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:*
cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:*
cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-08-24 11:16

Updated : 2026-09-02 14:43


NVD link : CVE-2026-76172

Mitre link : CVE-2026-76172

CVE.ORG link : CVE-2026-76172


JSON object : View

Products Affected

openjsf

  • fast-uri
CWE
CWE-177

Improper Handling of URL Encoding (Hex Encoding)