CVE-2026-6321

Summary

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 Software

VendorProductVersion RangeStatus
fast-urifast-uri0 < 3.1.1affected
fast-urifast-uri3.1.1unaffected

Weaknesses

  • CWE-22: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

fast-uri: fast-uri: Path traversal vulnerability allows bypass of security policies

Additional References

References