CVE-2026-126350

Addressable: Regular Expression Denial of Service in Addressable templates with certain exploded expressions

Published Nov 12, 2026 CVSS 3.1 · 5.9 Medium EPSS n/a KEV · Not listed
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 using the explode modifier with the slash, dot, semicolon, question-mark, or ampersand operators generate ambiguous regular expressions. When Template#match or Template#extract processes an attacker-controlled URI beginning with the operator's leading character, optional member separators allow catastrophic backtracking and denial of service on MRI Ruby before 3.2 and JRuby. Addressable 2.9.0 incompletely remediated the earlier template issue because its tests did not reach these operator-prefixed paths. URI parsing and Template#expand are unaffected. This issue is fixed in version 2.9.1.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-j82w-28jv-3pmj Addressable: Regular Expression Denial of Service in templates with certain exploded expressions
History
Type Values Removed Values Added
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 using the explode modifier with the slash, dot, semicolon, question-mark, or ampersand operators generate ambiguous regular expressions. When Template#match or Template#extract processes an attacker-controlled URI beginning with the operator's leading character, optional member separators allow catastrophic backtracking and denial of service on MRI Ruby before 3.2 and JRuby. Addressable 2.9.0 incompletely remediated the earlier template issue because its tests did not reach these operator-prefixed paths. URI parsing and Template#expand are unaffected. This issue is fixed in version 2.9.1.
Title Addressable: Regular Expression Denial of Service in Addressable templates with certain exploded expressions
Weaknesses CWE-1333
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

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Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Nov 12, 2026, 10:04 PM
Reserved
Nov 10, 2026, 9:12 PM
Status
Received
Published
Nov 12, 2026, 10:19 PM
Modified
Nov 12, 2026, 10:19 PM