# CVE-2026-126353: Addressable: Regular Expression Denial of Service in Addressable templates with several exploded 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 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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- sporkmonger / addressable: >= 2.3.0, < 2.9.1 (affected). Source: CNA: GitHub_M

## 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-4w5q-wg7v-w6gp (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/sporkmonger/addressable/commit/49aecf97bf6f6675717f1078a0b45f95c428e103 (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/49aecf97bf6f6675717f1078a0b45f95c428e103 (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-4w5q-wg7v-w6gp (security-advisories@github.com)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-126353; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126353; retrieved 2026-11-13; source updated 2026-11-12

Revision: 5be7d9310e8cb5036ea074c8220d5436c7270aa9ced5c79dc777fda700f826cd

Canonical: https://y2.dev/cve/CVE-2026-126353

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