CVE-2026-126353

Received Received - Intake

Addressable Ruby URI Template Regex DoS

Publication date: 2026-11-12

Last updated on: 2026-11-12

Assigner: GitHub, Inc.

Description

Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.3.0 until 2.9.1, URI template expressions containing several exploded variables generate ambiguous regular expressions that can divide a run of members among the variables in polynomially many ways. Template#match or Template#extract processing of an attacker-controlled URI can therefore consume a thread and cause denial of service. The flaw affects MRI Ruby before 3.2 and JRuby, TruffleRuby 40.0, and plus or number-sign expressions on MRI Ruby 3.2. MRI Ruby 3.3 and later, URI parsing, and Template#expand are unaffected. This issue is fixed in version 2.9.1.

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Meta Information

Published

2026-11-12

Last Modified

2026-11-12

Generated

2026-11-13

AI Q&A

2026-11-13

EPSS Evaluated

N/A

NVD

CVE-2026-126353

Affected Vendors & Products

Vendor	Product	Version / Range
ruby	ruby	2.9.1
ruby	ruby	From 2.3.0 (inc) to 3.2 (exc)
jruby	jruby	*
truffleruby	truffleruby	40.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-1333	The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.

Attack-Flow Graph

Executive Summary

This vulnerability affects the Addressable gem in Ruby, where URI template expressions with exploded variables generate ambiguous regular expressions. This can divide URI members in many ways, causing thread exhaustion and denial of service when processing attacker-controlled URIs.

Detection Guidance

Detecting this vulnerability requires checking the version of the Addressable gem in Ruby environments. Use the command 'gem list addressable' to see installed versions. If the version is below 2.9.1, the system is vulnerable.

Impact Analysis

An attacker could exploit this to consume system resources, leading to degraded performance or complete denial of service. Systems using vulnerable versions of Addressable (2.3.0 to 2.9.1) are at risk.

Mitigation Strategies

Upgrade the Addressable gem to version 2.9.1 or later using 'gem install addressable -v 2.9.1'. For Ruby MRI versions before 3.2, JRuby, or TruffleRuby, consider upgrading to a patched version of Ruby or the gem.

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