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Fencer Intel
medium 5.3

CVE-2026-128068 json

rails-html-sanitizer: Possible regular expression denial of service with certain configurations

published 13d ago modified yesterday also EUVD-2026-125592 , GHSA-cpgf-5mjf-73p7

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

rails-html-sanitizer is responsible for sanitizing HTML fragments in Rails applications. From 1.0.3 through 1.7.1, Rails::HTML::PermitScrubber checks SVG href and xlink:href local references with a pattern whose line-start anchor and whitespace class cause an all-whitespace value to be rescanned from each line start. An attacker who supplies HTML can cause quadratic CPU consumption when an application customizes its allowed tags to include an SVG reference element such as use and permits href or xlink:href. The default allowed tag configuration is not affected. CRuby 3.2 and later uses linear-time regular expression matching for this pattern, while CRuby 3.1 and earlier and JRuby are affected. This issue is fixed in version 1.7.2.

Patch / fix

  • rubygems rails-html-sanitizer 1.7.2

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Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
rubygems rails-html-sanitizer
>=1.0.3, <1.7.2
1.7.2

Affected products

  • rails rails-html-sanitizer

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-1333 Inefficient Regular Expression Complexity
Technology feeds

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 rails/rails-html-sanitizer published their own advisory on GitHub. Reviewed sources take precedence over it.