CVE catalog
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 st
- Severity
- Medium · CVSS 5.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.15% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | ruby-css-parser | sid | 3.3.0-1 | fixed |
| Debian | ruby-css-parser | forky | 3.3.0-1 | fixed |
| Debian | ruby-css-parser | trixie | 1.19.0-1+deb13u1 | fixed |
| Debian | ruby-css-parser | bookworm | 1.6.0-2+deb12u1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | ruby-css-parser | source | sid | 2.1.0-1 | not yet assigned | Not reported | Not reported |
| Debian | ruby-css-parser | source | forky | 2.1.0-1 | not yet assigned | Not reported | Not reported |
| Debian | ruby-css-parser | source | trixie | 1.19.0-1+deb13u1 | not yet assigned | Not reported | Not reported |
| Debian | ruby-css-parser | source | bookworm | 1.6.0-2+deb12u1 | not yet assigned | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [ruby-css-parser]Fixed
Details (2)
1.6.0-2+deb12u1· all · bookwormFixed · Fixed:
1.6.0-2+deb12u1nvd · ruby-css-parser · debian · bookworm; nvd · ruby-css-parser · debian · 12
1.6.0-2+deb12u1· all · bookwormFixed · Fixed:
1.6.0-2+deb12u1nvd · ruby-css-parser · debian · bookworm; nvd · ruby-css-parser · debian · 12
[Debian 13 (Trixie)]
- [ruby-css-parser]Fixed
Details (2)
1.19.0-1+deb13u1· all · trixieFixed · Fixed:
1.19.0-1+deb13u1nvd · ruby-css-parser · debian · 13
1.19.0-1+deb13u1· all · trixieFixed · Fixed:
1.19.0-1+deb13u1nvd · ruby-css-parser · debian · 13
Observed:
References
- [https://github.com/premailer/css_parser/commit/35e689c904225add78e0c488cf04bad052666449]
- [https://github.com/premailer/css_parser/commit/e0c95d5abe91b237becb90ff316531a6547ada18]
- [https://github.com/premailer/css_parser/issues/185]
- [https://github.com/premailer/css_parser/security/advisories/GHSA-ff6c-w6qf-7xqc]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-44312]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-44312]
- [https://security-tracker.debian.org/tracker/CVE-2026-44312]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44312.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]