CVE-2026-126351 Addressable: Denial of service in URI path normalization
Attacker-controlled URIs normalized by Addressable can cause quadratic work and deny service to Ruby apps joining untrusted paths.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Harmful if only installed
- No
- Needs a specific call
- Yes
- Fix
- Available
What is CVE-2026-126351?
CVE-2026-126351 is a medium-severity denial of service vulnerability in sporkmonger addressable, published on 12 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. Prior to 2.9.1, Addressable::URI.normalize_path repeatedly scans and rewrites paths while removing only one nested dot segment per pass, producing quadratic work. URI#normalize, URI#normalized_path, URI#join, URI#==, and URI#=== inherit the behavior, so processing a sufficiently long attacker-controlled URI can consume a worker thread and cause denial of service on every Ruby implementation. URI.parse alone and code that never normalizes, compares, or joins untrusted URIs are unaffected. This issue is fixed in version 2.9.1.
Weakness: CWE-407
Which versions are affected by CVE-2026-126351?
1 open source package ship an affected version, including addressable.
An affected version is only exploitable if your software calls Addressable::URI.normalize_path, URI#normalize or URI#normalized_path. Many projects that include it are not exposed.
| Package | Affected | Fixed in |
|---|---|---|
addressable RubyGems | All versions | 2.9.1 |
How do I fix CVE-2026-126351?
Upgrade addressable to 2.9.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-126351 being exploited?
There is no known exploitation of CVE-2026-126351 in the wild and no public exploit code.
Sources
Also known as AZL-113813, GHSA-qq38-m9mg-xjj5.