In the CGI gem before 0.4.2 for Ruby, a Regular Expression Denial of Service (ReDoS) vulnerability exists in the Util#escapeElement method. — CVE-2025-27220

Summary

Advisory CVE-2025-27220. In the CGI gem before 0.4.2 for Ruby, a Regular Expression Denial of Service (ReDoS) vulnerability exists in the Util#escapeElement method. Vendor: Microsoft. Source: MSRC. Threat: medium. CVSS 4. See the official…

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

Read the official source

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