Skip to main content

Boteraser | Website and Server Security Solutions

🛡️ CVE-2026-6322 — fast-uri

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-140 OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

fast-uri vulnerable to host confusion via percent-encoded authority delimiters

Impact

fast-uri v3.1.1 and earlier decodes percent-encoded authority delimiters (%40 as @, %3A as :) inside the host component and serializes them back as raw characters. This changes the URI structure, turning a hostname into userinfo plus a different host.

For example, http://trusted.com%40evil.com/ normalizes to http://[email protected]/, which reparses as host evil.com with userinfo trusted.com.

Applications that normalize untrusted URLs before host allowlist checks, redirect validation, or outbound request routing can be steered to a different authority than the original URL appeared to contain.

Patches

Upgrade to fast-uri >= 3.1.2, or if you are in the v2.x release line, v2.4.1

Workarounds

None. Upgrade to the patched version.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2026-6322 is classified as CWE-140: Improper Neutralization of Delimiters. The product does not neutralize or incorrectly neutralizes delimiters.

Affected software

CVE-2026-6322 is recorded against 1 package.

  • fast-uri

Timeline and source

Published on 8 May 2026 and last revised on 20 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
nvd.nist.gov (Advisory)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
bugzilla.redhat.com (Web)
cna.openjsf.org (Web)
github.com (Package)
github.com (Web)
github.com (Web)
security.access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)

Other advisories for this package

fast-uri has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-140: Improper Neutralization of Delimiters) in other software:

CVE-2026-6322 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE CWE-140
Public Exploit ✅ No
Source OSV
Published 2026-05-08
Updated 2026-08-20
Modified 2026-08-20
Fix URL N/A

Affected Packages

Software From version Fixed in
fast-uri

References

Site Security Check

Is fast-uri part of your stack?

CVE-2026-6322 is rated CVSS 8.0 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

Scan My Site Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesCVECVE 2026