fast-uri vulnerable to path traversal via percent-encoded dot segments
Summary
| CVE | CVE-2026-6321 |
|---|---|
| State | PUBLISHED |
| Assigner | openjs |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-04 20:16:20 UTC |
| Updated | 2026-05-12 18:54:46 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from ce714d77-add3-4f53-aff5-83d477b104bb
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS: 0.000390000 probability, percentile 0.117130000 (date 2026-05-12)
Problem Types: CWE-22 | CWE-22 CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ce714d77-add3-4f53-aff5-83d477b104bb | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| 3.1 | CNA | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
HighAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| cna.openjsf.org/security-advisories.html | ce714d77-add3-4f53-aff5-83d477b104bb | cna.openjsf.org | Vendor Advisory |
| github.com/fastify/fast-uri/security/advisories/GHSA-q3j6-qgpj-74h6 | ce714d77-add3-4f53-aff5-83d477b104bb | github.com | Vendor Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Jvr (en)
CNA: Matteo Collina (en)
CNA: Ulises Gascón (en)
CNA: KaKa (en)
There are currently no legacy QID mappings associated with this CVE.