CVE-2023-45143: Fedoraproject Fedora

Low severity, CVSS 3.5. EPSS: 1.2% chance of exploitation in the next 30 days.

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 `Cookie` headers. By design, `cookie` headers are forbidden request headers, disallowing them to be set in RequestInit.headers in browser environments. Since undici handles headers more liberally than the spec, 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 third-party site or a malicious attacker who can control the redirection target (ie. an open redirector) to leak the cookie to the third party site. This was patched in version 5.26.2. There are no known workarounds.

Affected products

• Fedoraproject Fedora: version 37 only; version 38 only; version 39 only
• Node.js Undici: before 5.26.2 (fixed in 5.26.2)

Published 2023-10-12. Last modified 2026-06-17.