PatchTheCVECVE-2026-6321: fast-uri decoded percent-encoded path separators and dot segments before applying dot-segment removal in its n
CVE-2026-6321 is a high-severity flaw (CVSS 7.5) affecting fast-uri. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 p
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.6% (top 50%) |
| CISA exploited list | No |
| Weakness | CWE-22 |
| Published | 2026-05-04 |
| Last modified | 2026-09-10 |
Last updated 2026-09-10 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-6321?
fast-uri: upgrade to 3.1.1. Exact commands for each OS are on this page.
Is CVE-2026-6321 being exploited?
CVE-2026-6321 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-6321 affect?
CVE-2026-6321 affects fast-uri. Severity is high (CVSS 7.5). 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 URI
How urgent is CVE-2026-6321?
Priority 44/100. High severity; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2026-75931 HIGH 7.5 UPGRADE fast-uri is a URI parser for Node.js
- CVE-2026-76172 HIGH 7.5 UPGRADE fast-uri is a URI parser for Node.js
- CVE-2026-75899 HIGH 7.5 UPGRADE fast-uri is a URI parser for Node.js
- CVE-2026-75975 HIGH 7.5 UPGRADE fast-uri is a URI parser for Node.js
- CVE-2026-84292 HIGH 7.5 UPGRADE fast-uri serializes the port component of a URI without validating it