# CVE-2026-126353: Addressable URI template regular expression denial of service

Source: https://junglewise.ai/threats/cve-2026-126353-addressable-is-an-alternative-implementation-to-the-uri  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-12. Updated: 2026-11-12  
License: CC BY 4.0 with a link back

CVE-2026-126353 · Severity: medium · CVSS 5.9 · Published 2026-11-12

Addressable is a Ruby library that parses and manipulates URIs and URI templates. Versions 2.3.0 through 2.9.0 are vulnerable to a denial of service attack when processing attacker-controlled URI template expressions with multiple exploded variables, which can cause the template matching to consume excessive CPU and hang a thread. An attacker could exploit this to make an application unresponsive.

## Quick answers

**Is CVE-2026-126353 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-126353 being exploited in the wild.

**How severe is CVE-2026-126353?** Medium severity, with a CVSS score of 5.9, published 12 November 2026.

**Which products and versions are affected?** Sporkmonger Addressable 2.3.0 to 2.9.0.

**Is there a fix for CVE-2026-126353?** Yes: fixed in 2.9.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-126353 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-126353?** Check whether you run Sporkmonger Addressable at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 2.9.1

## Technical details

The vulnerability exists in URI template expression processing where exploded variables with certain operators (/, ., ;, ?, &, +, #) generate ambiguous regular expressions that match input strings in polynomially or exponentially many ways. On regex engines without match memoization (MRI Ruby before 3.2, JRuby, TruffleRuby), processing Template#match or Template#extract with a crafted input triggers catastrophic backtracking. Ruby 3.2 is affected for plus and number-sign expressions; Ruby 3.3+ and URI#parse are unaffected.

## Affected products

- sporkmonger Addressable 2.3.0 to 2.9.0

## Timeline

- 2026-11-12: disclosed
- 2026-10-30: patched

## References

- [https://github.com/sporkmonger/addressable/commit/49aecf97bf6f6675717f1078a0b45f95c428e103](https://github.com/sporkmonger/addressable/commit/49aecf97bf6f6675717f1078a0b45f95c428e103)
- [https://github.com/sporkmonger/addressable/releases/tag/addressable-2.9.1](https://github.com/sporkmonger/addressable/releases/tag/addressable-2.9.1)

## Related threats

- [Addressable URI.normalize_path path traversal and bypass](https://junglewise.ai/threats/cve-2026-126354-addressable-uri-normalization-resolves-some-dotted-path-segments)