CVE-2026-44312: CWE-829: Inclusion of Functionality from Untrusted Control Sphere in premailer css_parser
The css_parser Ruby gem versions prior to 2. 1. 0 and 1. 22. 0 do not validate HTTPS certificates when loading stylesheets, accepting any certificate without verification. This allows a Man-in-the-Middle (MITM) attacker to inject or modify CSS content by exploiting the lack of certificate validation. The vulnerability is fixed in versions 2. 1. 0 and 1. 22.
AI Analysis
Technical Summary
CVE-2026-44312 affects the premailer css_parser Ruby gem where HTTPS connections are established with OpenSSL::SSL::VERIFY_NONE, disabling certificate validation. This flaw enables attackers positioned as MITM to alter or inject malicious CSS content during stylesheet loading over HTTPS. The issue is resolved in css_parser versions 2.1.0 and 1.22.0 by enforcing proper HTTPS certificate validation.
Potential Impact
An attacker capable of intercepting HTTPS traffic can modify CSS content loaded by vulnerable versions of css_parser, potentially influencing the appearance or behavior of applications relying on this gem. The vulnerability does not impact confidentiality or availability but allows integrity compromise of CSS resources.
Mitigation Recommendations
Upgrade css_parser to version 2.1.0 or later, or 1.22.0 or later, where HTTPS certificate validation is properly enforced. No other mitigations are specified. Patch status is confirmed fixed in these versions.
CVE-2026-44312: CWE-829: Inclusion of Functionality from Untrusted Control Sphere in premailer css_parser
Description
The css_parser Ruby gem versions prior to 2. 1. 0 and 1. 22. 0 do not validate HTTPS certificates when loading stylesheets, accepting any certificate without verification. This allows a Man-in-the-Middle (MITM) attacker to inject or modify CSS content by exploiting the lack of certificate validation. The vulnerability is fixed in versions 2. 1. 0 and 1. 22.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-44312 affects the premailer css_parser Ruby gem where HTTPS connections are established with OpenSSL::SSL::VERIFY_NONE, disabling certificate validation. This flaw enables attackers positioned as MITM to alter or inject malicious CSS content during stylesheet loading over HTTPS. The issue is resolved in css_parser versions 2.1.0 and 1.22.0 by enforcing proper HTTPS certificate validation.
Potential Impact
An attacker capable of intercepting HTTPS traffic can modify CSS content loaded by vulnerable versions of css_parser, potentially influencing the appearance or behavior of applications relying on this gem. The vulnerability does not impact confidentiality or availability but allows integrity compromise of CSS resources.
Mitigation Recommendations
Upgrade css_parser to version 2.1.0 or later, or 1.22.0 or later, where HTTPS certificate validation is properly enforced. No other mitigations are specified. Patch status is confirmed fixed in these versions.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-05T19:00:06.022Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a05fd9fec166c07b0f93177
Added to database: 5/14/2026, 4:51:43 PM
Last enriched: 5/14/2026, 5:08:20 PM
Last updated: 5/15/2026, 7:36:40 AM
Views: 7
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