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Vulnerabilities

Vulnerability · CVE-2026-44312

css_parser is a Ruby CSS parser.

Published May 14, 2026 · catalog updated Jun 17, 2026 · css_parser is a Ruby

Check if you run it

No confirmed exploitation is on record for CVE-2026-44312. EPSS is 0.24%. Act only if a listed version of css_parser is a Ruby is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (css_parser is a Ruby).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.24%
Remediation
Advisory link
Affected products
See sources for product scope

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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-44312

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-44312. EPSS is 0.24%. Act only if a listed version of css_parser is a Ruby is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-295: Improper Certificate Validation; CWE-829: Inclusion of Functionality from Untrusted Control Sphere. EPSS 0.24%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 14, 2026 · NIST NVD

    Detected

    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 vulnerabil

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 vulnerabil

Sources

  • CVE.orgVulnerability recordCVE-2026-44312

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-44312

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-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 connection is established with OpenSSL::SSL:

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.