CVE-2026-44312

Name	CVE-2026-44312
Description	css_parser is a Ruby CSS parser. Prior to 2.1.0 and 1.22.0, the CSS Parser gem does not validate HTTPS connections, allowing a Man-in-the-Middle (MITM) attacker to inject or modify CSS content when stylesheets are loaded via HTTPS. The connection is established with OpenSSL::SSL::VERIFY_NONE, meaning any HTTPS certificate—even entirely untrusted—will be accepted without validation. This vulnerability is fixed in 2.1.0 and 1.22.0.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
ruby-css-parser (PTS)	bullseye	1.6.0-1	vulnerable
	bookworm	1.6.0-2	vulnerable
	trixie	1.19.0-1	vulnerable
	forky, sid	2.1.0-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
ruby-css-parser	source	(unstable)	2.1.0-1

Notes

https://github.com/premailer/css_parser/security/advisories/GHSA-ff6c-w6qf-7xqc
https://github.com/premailer/css_parser/issues/185
Fixed by: https://github.com/premailer/css_parser/commit/35e689c904225add78e0c488cf04bad052666449 (v2.1.0)
Fixed by: https://github.com/premailer/css_parser/commit/e0c95d5abe91b237becb90ff316531a6547ada18 (v1.22.0)