CVE-2026-6321: Openjsf Fast-Uri

High severity, CVSS 7.5. EPSS: 0.8% chance of exploitation in the next 30 days.

fast-uri decoded percent-encoded path separators and dot segments before applying dot-segment removal in its normalize() and equal() functions. Encoded path data was treated like real slashes and parent-directory references, so distinct URIs could collapse onto the same normalized path. Applications that normalize or compare attacker-controlled URLs to enforce path-based policy can be bypassed, with a path that appears confined under an allowed prefix normalizing to a different location. Versions <= 3.1.0 are affected. Update to 3.1.1 or later.

Affected products

• Openjsf Fast-Uri: before 3.1.1 (fixed in 3.1.1)

Published 2026-05-04. Last modified 2026-09-10.