CVE-2022-31099 is a medium-severity (CVSS 6.5) CWE-674 vulnerability in rulex. O3 Security confirms whether CVE-2022-31099 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Uncontrolled Recursion in rulex
Real-World Exposure
rulexReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
rulex is a new, portable, regular expression language. When parsing untrusted rulex expressions, the stack may overflow, possibly enabling a Denial of Service attack. This happens when parsing an expression with several hundred levels of nesting, causing the process to abort immediately. This is a security concern for you, if your service parses untrusted rulex expressions (expressions provided by an untrusted user), and your service becomes unavailable when the process running rulex aborts due to a stack overflow. The crash is fixed in version 0.4.3. Affected users are advised to update to this version. There are no known workarounds for this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | rulex | all versions | 0.4.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rulex. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update rulex to 0.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-31099 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 pinpoints whether CVE-2022-31099 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2022-31099. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2022-31099 in your dependencies?
O3 detects CVE-2022-31099 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.