Vulnerability in Premailer Css_parser
CVE-2026-44312
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 con…
Vulnerability class: Improper Certificate Validation
EPSS: 0.000 (6.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N.
Affected products
- Premailer Css_parser — versions >= 2.0.0, < 2.1.0, < 1.22.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-44312?
- CVE-2026-44312 is a medium-severity vulnerability in Premailer Css_parser, classified under Improper Certificate Validation. CVSS score: 5.8/10. Published 2026-05-14.
- How severe is CVE-2026-44312?
- Medium severity. CVSS v3 base score is 5.8 out of 10.