CVE-2026-35611 (High) detected in addressable-2.8.9.gem

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
72/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Quiet
Tech stack
ruby
Domain
security

Research direction

Start with /Gemfile.lock and /vendor/cache/addressable-2.8.9.gem, then trace the dependency hierarchy through json-schema, mcp, rubocop, and rubocop-performance. Update addressable from 2.8.9 to the fixed 2.9.0 release and confirm the vulnerable library is no longer present in the dependency files.

Written by the indexing model from the issue text.

Description

Mend: dependency security vulnerability

CVE-2026-35611 - High Severity Vulnerability

Vulnerable Library - addressable-2.8.9.gem

Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. It is flexible, offers heuristic parsing, and additionally provides extensive support for IRIs and URI templates.

Library home page: https://rubygems.org/gems/addressable-2.8.9.gem

Path to dependency file: /Gemfile.lock

Path to vulnerable library: /vendor/cache/addressable-2.8.9.gem

Dependency Hierarchy:

  • manageiq-style-1.6.0.gem (Root Library)
    • rubocop-performance-1.26.1.gem
      • rubocop-1.85.1.gem
        • mcp-0.9.0.gem
          • json-schema-6.2.0.gem
            • ❌ addressable-2.8.9.gem (Vulnerable Library)

Found in base branch: master

Vulnerability Details

Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.3.0 to before 2.9.0, within the URI template implementation in Addressable, two classes of URI template generate regular expressions vulnerable to catastrophic backtracking. Templates using the * (explode) modifier with any expansion operator (e.g., {foo*}, {+var*}, {#var*}, {/var*}, {.var*}, {;var*}, {?var*}, {&var*}) generate patterns with nested unbounded quantifiers that are O(2^n) when matched against a maliciously crafted URI. Templates using multiple variables with the + or # operators (e.g., {+v1,v2,v3}) generate patterns with O(n^k) complexity due to the comma separator being within the matched character class, causing ambiguous backtracking across k variables. When matched against a maliciously crafted URI, this can result in catastrophic backtracking and uncontrolled resource consumption, leading to denial of service. This vulnerability is fixed in 2.9.0.

Publish Date: 2026-04-07

URL: CVE-2026-35611

CVSS 3 Score Details (7.5)

Base Score Metrics:

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

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Release Date: 2026-04-07

Fix Resolution: https://github.com/sporkmonger/addressable.git - addressable-2.9.0

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Dominant language
Ruby
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Forks
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