CVE-2026-84394

node-ajv: fast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an error

CVE-2026-84394 is fixed in node-ajv on 1 platform by DEBIAN-CVE-2026-84394 (version 8.20.0~ds+~cs7.1.5-1), released September 10, 2026. It is not reported as exploited. Patch Radar priority: High.

High
CVSS
7.5
high
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0038
32nd percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
node-ajv · Debian 14 8.20.0~ds+~cs7.1.5-1 DEBIAN-CVE-2026-84394 Sep 10, 2026

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