CVE-2026-84394 (GCVE-0-2026-84394)

Vulnerability from cvelistv5 – Published: 2026-09-02 20:25 – Updated: 2026-09-03 13:14
VLAI
Title
fast-uri vulnerable to host confusion via an unclosed bracket in the URI authority
Summary
fast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an error. A host that starts with an opening bracket but does not end with a closing bracket is neither validated as an IP literal nor canonicalized as a domain name, so parse() returns it as the host with error undefined, while Node's URL and the HTTP clients built on it resolve the same string to a different host. An application that reads the parsed host to make a host decision, such as an SSRF denylist, a redirect allowlist, or proxy routing, and then passes the original URL to an HTTP client evaluates its policy against a string that is not the host the request reaches. The same host is carried through normalize, equal, and resolve. This affects fast-uri versions 2.4.5, 3.1.6, and 4.1.3, and is fixed in 2.4.6, 3.1.7, and 4.1.4, where parse() reports a malformed host for any host that contains a bracket but is not a valid IPv6 literal.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-03 13:14 UTC
CWE
  • CWE-436 - Interpretation Conflict
Assigner
openjs CNA under the redhat root
CNA scorecard C 66/100 over 142 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
fast-uri fast-uri Affected: 2.4.5 , < 2.4.6 (semver)
Unaffected: 2.4.6 (semver)
Affected: 3.1.6 , < 3.1.7 (semver)
Unaffected: 3.1.7 (semver)
Affected: 4.1.3 , < 4.1.4 (semver)
Unaffected: 4.1.4 (semver)
guessed Create a notification for this product.
Credits
YashvantHange mcollina UlisesGascon
Show details on NVD website
To clipboard 

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