# CVE-2026-126352: Addressable: Regular Expression Denial of Service in Addressable templates with multiple variables

Status: published. Published: 2026-11-12. Updated: 2026-11-12.

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 templates with several variables in one expression or several adjacent expressions generate ambiguous regular expressions. Affected forms include multi-variable expressions using operators other than plus and number sign, large plus or number-sign expressions, and adjacent single-variable expressions. Template#match or Template#extract can backtrack polynomially or exponentially on attacker-controlled URIs, causing denial of service on MRI Ruby before 3.2 and JRuby, with the large plus and number-sign form also affecting MRI Ruby 3.2 and TruffleRuby 40.0. URI parsing and Template#expand are unaffected. This issue is fixed in version 2.9.1.

## Remediation

- fix: addressable (RubyGems): OSV reports a fixed version 2.9.1. Check the advisory for supported release branches. (source: OSV GHSA-9f42-57jx-vpp3) — https://github.com/advisories/GHSA-9f42-57jx-vpp3

## Affected products and versions

- sporkmonger / addressable: >= 2.3.0, < 2.9.1 (affected). Source: CNA: GitHub_M
-  / addressable (addressable): 2.3.2 (affected, RubyGems); 2.3.3 (affected, RubyGems); 2.3.4 (affected, RubyGems); 2.3.5 (affected, RubyGems); 2.3.6 (affected, RubyGems); 2.3.7 (affected, RubyGems); 2.3.8 (affected, RubyGems); 2.4.0 (affected, RubyGems); 2.5.0 (affected, RubyGems); 2.5.1 (affected, RubyGems); 2.5.2 (affected, RubyGems); 2.6.0 (affected, RubyGems); 2.7.0 (affected, RubyGems); 2.8.0 (affected, RubyGems); 2.8.1 (affected, RubyGems); 2.8.10 (affected, RubyGems); 2.8.2 (affected, RubyGems); 2.8.3 (affected, RubyGems); 2.8.4 (affected, RubyGems); 2.8.5 (affected, RubyGems); 2.8.6 (affected, RubyGems); 2.8.7 (affected, RubyGems); 2.8.8 (affected, RubyGems); 2.8.9 (affected, RubyGems); 2.9.0 (affected, RubyGems); Ecosystem version events: introduced 2.3.0; fixed 2.9.1. Source: OSV GHSA-9f42-57jx-vpp3

## Severity and prioritization

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: GitHub_M

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-1333

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/sporkmonger/addressable/security/advisories/GHSA-9f42-57jx-vpp3 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/sporkmonger/addressable/commit/f2b27b3ab252e56b3fa3519f7ebb491d54cf7b7c (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sporkmonger/addressable/releases/tag/addressable-2.9.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/sporkmonger/addressable/commit/f2b27b3ab252e56b3fa3519f7ebb491d54cf7b7c (security-advisories@github.com)

- https://github.com/sporkmonger/addressable/releases/tag/addressable-2.9.1 (security-advisories@github.com)

- https://github.com/sporkmonger/addressable/security/advisories/GHSA-9f42-57jx-vpp3 (security-advisories@github.com)

- https://github.com/advisories/GHSA-9f42-57jx-vpp3 (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-9f42-57jx-vpp3 (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-126352; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126352; retrieved 2026-11-13; source updated 2026-11-12

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-9f42-57jx-vpp3; retrieved 2026-11-12; source updated 2026-11-12

Revision: 4292321d93efd508c6f31316bd7bb09448173a5db837b111d67fae394cb57fbb

Canonical: https://y2.dev/cve/CVE-2026-126352

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