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Inefficient Regular Expression Complexity in rails-html-sanitizer

High severity GitHub Reviewed Published Dec 13, 2022 in rails/rails-html-sanitizer • Updated Nov 4, 2025

Package

bundler rails-html-sanitizer (RubyGems)

Affected versions

< 1.4.4

Patched versions

1.4.4

Description

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

References

@flavorjones flavorjones published to rails/rails-html-sanitizer Dec 13, 2022
Published to the GitHub Advisory Database Dec 13, 2022
Reviewed Dec 13, 2022
Published by the National Vulnerability Database Dec 14, 2022
Last updated Nov 4, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(50th percentile)

Weaknesses

Inefficient Regular Expression Complexity

The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles. Learn more on MITRE.

CVE ID

CVE-2022-23517

GHSA ID

GHSA-5x79-w82f-gw8w

Source code

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