GHSA-xx4j-rvcc-2vhr is a medium-severity (CVSS 5.5) Out-of-bounds Read vulnerability in capstone. 1 public exploit reference exists, so weaponization risk is real. A fix is available for capstone — see the affected versions and patch details below.
Capstone SEGV caused by a read memory access
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-xx4j-rvcc-2vhr 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 377,166 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
capstoneReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Capstone 3.0.4 has an out-of-bounds vulnerability (SEGV caused by a read memory access) in X86_insn_reg_intel in arch/X86/X86Mapping.c.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | capstone | all versions | 4.0.0pip install --upgrade 'capstone==4.0.0' |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for capstone, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update capstone to 4.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xx4j-rvcc-2vhr 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-xx4j-rvcc-2vhr can be triaged on real exposure rather than presence alone.
Tailored to GHSA-xx4j-rvcc-2vhr. 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-xx4j-rvcc-2vhr in your dependencies?
O3 Security finds GHSA-xx4j-rvcc-2vhr across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.