Vulnerability 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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/premailer/css_parser/commit/35e689c904225add78e0c488cf04bad05
- https://github.com/premailer/css_parser/commit/e0c95d5abe91b237becb90ff316531a65
- https://github.com/premailer/css_parser/issues/185
- https://github.com/premailer/css_parser/security/advisories/GHSA-ff6c-w6qf-7xqc
- https://github.com/premailer/css_parser/security/advisories/GHSA-ff6c-w6qf-7xqc
FAQ
What is CVE-2026-44312?
CVE-2026-44312 is a vulnerability with a CVSS score of 5.8 (MEDIUM). 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 st...
How severe is CVE-2026-44312?
CVE-2026-44312 has been rated MEDIUM with a CVSS base score of 5.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-44312?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.