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.

PUBLISHED Reserved 2026-05-05 | Published 2026-05-14 | Updated 2026-05-15 | Assigner GitHub_M

Problem types

CWE-829: Inclusion of Functionality from Untrusted Control Sphere

CWE-295: Improper Certificate Validation

Product status

References

github.com/...parser/security/advisories/GHSA-ff6c-w6qf-7xqc exploit

github.com/...parser/security/advisories/GHSA-ff6c-w6qf-7xqc

github.com/premailer/css_parser/issues/185

github.com/...ommit/35e689c904225add78e0c488cf04bad052666449

github.com/...ommit/e0c95d5abe91b237becb90ff316531a6547ada18

cve.org (CVE-2026-44312)

nvd.nist.gov (CVE-2026-44312)

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