CVE-2026-44312CWE-295CWE-829

css_parser allows to MITM included https css urls

Medium · published May 14, 2026

CVSS v3.1
5.8
EPSS
0%
Percentile
14.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.8 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00241 · 14.3th percentile
Weaknesses
CWE-295 · Improper Certificate Validation; CWE-829 · Inclusion of Functionality from Untrusted Control Sphere
Published
2026-05-14T16:15Z
EPSS history
Timeline
  • 14 MAY 16:15Z
    css_parser allows to MITM included https css urls
    cvelistv5