CVE-2023-46218: Fedoraproject Fedora

Medium severity, CVSS 6.5. EPSS: 1.7% chance of exploitation in the next 30 days.

This flaw allows a malicious HTTP server to set "super cookies" in curl that are then passed back to more origins than what is otherwise allowed or possible. This allows a site to set cookies that then would get sent to different and unrelated sites and domains. It could do this by exploiting a mixed case flaw in curl's function that verifies a given cookie domain against the Public Suffix List (PSL). For example a cookie could be set with `domain=co.UK` when the URL used a lower case hostname `curl.co.uk`, even though `co.uk` is listed as a PSL domain.

Affected products

• Fedoraproject Fedora: version 39 only
• Haxx Curl: from 7.46.0, up to and including 8.4.0

Published 2023-12-07. Last modified 2026-06-17.