CVE-2022-23516 is a high-severity (CVSS 7.5) CWE-674 vulnerability in loofah. A fix is available for loofah — see the affected versions and patch details below.
Uncontrolled Recursion in Loofah
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-23516.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2022-23516 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 >= 2.2.0, < 2.19.1 uses recursion for sanitizing CDATA sections, making it susceptible to stack exhaustion and raising a SystemStackError exception. This may lead to a denial of service through CPU resource consumption.
Mitigation
Upgrade to Loofah >= 2.19.1.
Users who are unable to upgrade may be able to mitigate this vulnerability by limiting the length of the strings that are sanitized.
Severity
The Loofah maintainers have evaluated this as High Severity 7.5 (CVSS3.1).
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | loofah | ≥ 2.2.0&&< 2.19.1 | 2.19.1bundle update loofah --conservative |
Detection & 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 CVE-2022-23516 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-23516 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-23516. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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 | tfm-rubygem-loofah-0:2.19.1-1.el8sat | RHSA-2023:2097 |
Frequently Asked Questions
Is CVE-2022-23516 in your dependencies?
O3 Security finds CVE-2022-23516 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.