GHSA-wqq4-5wpv-mx2g

ghsaUSosv

Undici's cookie header not cleared on cross-origin redirect in fetch

view advisory published 2023-10-16Licence: CC-BY-4.0

### Impact Undici clears Authorization headers on cross-origin redirects, but does not clear `Cookie` headers. By design, `cookie` headers are [forbidden request headers](https://fetch.spec.whatwg.org/#forbidden-request-header), disallowing them to be set in `RequestInit.headers` in browser environments. Since Undici handles headers more liberally than the specification, there was a disconnect from the assumptions the spec made, and Undici's implementation of fetch. As such this may lead to accidental leakage of cookie to a 3rd-party site or a malicious attacker who can control the redirection target (ie. an open redirector) to leak the cookie to the 3rd party site. ### Patches This was patched in [e041de359221ebeae04c469e8aff4145764e6d76](https://github.com/nodejs/undici/commit/e041de359221ebeae04c469e8aff4145764e6d76), which is included in version 5.26.2.

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describes (1)

Related CVEs.

IDseverity exploitable
CVE-2023-45143USlow3.5—
Undici is an HTTP/1.1 client written from scratch for Node.js. Prior to version 5.26.2, Undici already cleared Authorization headers on cross-origin redirects, but did not clear `C…
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