CVE-2026-44312
Published:May 14, 2026
Updated:May 18, 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.
Affected Packages
https://github.com/premailer/css_parser.git (GITHUB):
Affected version(s) =v2.0.0 <v2.1.0Fix Suggestion:
Update to version v2.1.0https://github.com/premailer/css_parser.git (GITHUB):
Affected version(s) >=v1.3.0 <v1.22.0Fix Suggestion:
Update to version v1.22.0css_parser (RUBY):
Affected version(s) =2.0.0 <2.1.0Fix Suggestion:
Update to version 2.1.0css_parser (RUBY):
Affected version(s) >=0.9.0 <1.22.0Fix Suggestion:
Update to version 1.22.0css_parser (RUBY):
Affected version(s) >=0.9.0 <1.22.0Fix Suggestion:
Update to version 1.22.0Related Resources (6)
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Contact UsCVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
LOW
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.8
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
EPSS
Base Score:
0.02