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Fencer Intel
medium 5.9

CVE-2026-126353 json

Addressable: Regular Expression Denial of Service in Addressable templates with several exploded variables

published 16d ago modified yesterday also EUVD-2026-124733 , GHSA-4w5q-wg7v-w6gp

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository sporkmonger/addressable. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

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.

Patch / fix

Is CVE-2026-126353 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • sporkmonger addressable

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of sporkmonger/addressable published their own advisory on GitHub. Reviewed sources take precedence over it.