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CVE-2026-6321

HIGHCVSS 7.5/10EPSS 0.52%

Last modified

CVE-2026-6321 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.52% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability
0.52%

40.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
OpenjsfFast-Uri< 3.1.1

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-6321?
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.
How severe is CVE-2026-6321?
CVE-2026-6321 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.52% probability of exploitation in the next 30 days.
How do I fix CVE-2026-6321?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST