GHSA-v78m-2q7v-fjqp is a medium-severity (CVSS 6.5) CWE-674 vulnerability in rulex. A fix is available for rulex — see the affected versions and patch details below.
Uncontrolled Recursion in rulex
Exploitation Status
No confirmed exploitation observed yet
- 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 GHSA-v78m-2q7v-fjqp.
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
GHSA-v78m-2q7v-fjqp 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 379,145 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
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
Impact
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.
Patches
The crash is fixed in version 0.4.3. Affected users are advised to update to this version.
Workarounds
None.
For more information
If you have any questions or comments about this advisory:
- Open an issue in rulex
- Email me at [email protected]
Credits
Credit for finding these bugs goes to
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | rulex | all versions | 0.4.3cargo update -p rulex --precise 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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rulex to 0.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v78m-2q7v-fjqp 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 GHSA-v78m-2q7v-fjqp can be triaged on real exposure rather than presence alone.
Tailored to GHSA-v78m-2q7v-fjqp. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-v78m-2q7v-fjqp in your dependencies?
O3 Security finds GHSA-v78m-2q7v-fjqp across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.