CVE-2026-126350

5.9 MEDIUM Fix listed Denial of service Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of service disruption.
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-11-10 21:12 UTC ReservedThe CVE id was reserved by its CNA
2026-11-12 22:19 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-11-12 22:19 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: not scored yet.
Severity: 5.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-11-12 22:19 UTC
Last modified: 2026-11-12 22:19 UTC
Weakness: CWE-1333
Record status: Received

Attack profile CVSS 3.1 · 5.9

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-126350.md and follow it. Check whether this project is affected by CVE-2026-126350. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record