GHSA-v39h-62p7-jpjc

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

Source: GitHub Advisory Database (reviewed) High CVE-2026-6322

Packages

Ecosystem	Package	Affected	Fixed in
npm	fast-uri	>= 3.0.0, < 3.1.2	3.1.2
npm	fast-uri	< 2.4.1	2.4.1

Details

As written in the advisory (Markdown source, shown as plain text).

### 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.

References

External links from the advisory. They lead to third-party sites.