Inefficient Regular Expression Complexity in LoofahGHSA-486f-hjj9-9vhh
HIGHFix: flavorjones/loofah@a6e0a1aGHSA-486f-hjj9-9vhh is a high-severity (CVSS 7.5) CWE-1333 vulnerability in loofah. A fix is available for loofah — see the affected versions and patch details below.
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-486f-hjj9-9vhh.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
loofahReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Loofah < 2.19.1 contains 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 Loofah >= 2.19.1.
Severity
The Loofah maintainers have evaluated this as High Severity 7.5 (CVSS3.1).
References
- CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
- https://hackerone.com/reports/1684163
Credit
This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | loofah | all versions | 2.19.1bundle update loofah --conservative |
Affected Products
loofahloofah_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for loofah, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update loofah to 2.19.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-486f-hjj9-9vhh is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Satellite 6.13 for RHEL 8 | satellite:el8/rubygem-loofah-0:2.19.1-1.el8sat | RHSA-2023:2097 |
Frequently Asked Questions
Is GHSA-486f-hjj9-9vhh in your dependencies?
Find it across RubyGems, including transitive dependencies.