CVE-2026-33170 (Medium) detected in activesupport-8.0.4.gem

[mend-bolt-for-github]

CVE-2026-33170 - Medium Severity Vulnerability

Vulnerable Library - activesupport-8.0.4.gem

A toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Rich support for multibyte strings, internationalization, time zones, and testing.

Library home page: https://rubygems.org/gems/activesupport-8.0.4.gem

Path to dependency file: /Gemfile.lock

Path to vulnerable library: /tmp/containerbase/cache/.ruby/cache/activesupport-8.0.4.gem

Dependency Hierarchy:

• gettext_i18n_rails_js-1.3.1.gem (Root Library)
  • rails-8.0.4.gem
    • ❌ activesupport-8.0.4.gem (Vulnerable Library)

Found in base branch: master

Vulnerability Details

Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, "SafeBuffer#%" does not propagate the "@html_unsafe" flag to the newly created buffer. If a "SafeBuffer" is mutated in place (e.g. via "gsub!") and then formatted with "%" using untrusted arguments, the result incorrectly reports "html_safe? == true", bypassing ERB auto-escaping and possibly leading to XSS. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

Publish Date: 2026-03-23

URL: CVE-2026-33170

CVSS 3 Score Details (4.3)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: Low
  • Privileges Required: None
  • User Interaction: Required
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: None
  • Integrity Impact: Low
  • Availability Impact: None

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Release Date: 2026-03-23

Fix Resolution: https://github.com/rails/rails.git - v8.0.4.1,https://github.com/rails/rails.git - v7.2.3.1,https://github.com/rails/rails.git - v8.1.2.1,https://github.com/rails/rails.git - v8.1.3,https://github.com/rails/rails.git - v8.0.5

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