CVE-2026-44312
css_parser allows to MITM included https css urls
- State
- Published
- Severity
- 5.8 Medium
- Published
- May 14, 2026
- Updated
- May 15, 2026
- Reserved
- May 5, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.8 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N | GitHub_M |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
css_parserpremailer |
|
References
- https://github.com/premailer/css_parser/security/advisories/GHSA-ff6c-w6qf-7xqc
- https://github.com/premailer/css_parser/issues/185
- https://github.com/premailer/css_parser/commit/35e689c904225add78e0c488cf04bad052666449
- https://github.com/premailer/css_parser/commit/e0c95d5abe91b237becb90ff316531a6547ada18
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