GHSA-4cxw-hq44-r344 is a critical-severity (CVSS 9.1) CWE-193 vulnerability in github.com/v2fly/v2ray-core/v4. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-4cxw-hq44-r344 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Off-by-one Error in v2fly/v2ray-core
Real-World Exposure
github.com/v2fly/v2ray-core/v4🐹github.com/v2fly/v2ray-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
v2fly/v2ray-core prior to 4.44.0 is vulnerable to an off-by-one error. Indexing operations on arrays, slices, or strings should use an index at most one less than the length. If the index is checked for being less than or equal to the length (<=), instead of less than the length (<), the index could be out of bounds.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/v2fly/v2ray-core/v4 | all versions | 4.44.0 |
| 🐹Go | github.com/v2fly/v2ray-core | all versions | No fix |
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 github.com/v2fly/v2ray-core/v4. 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 github.com/v2fly/v2ray-core/v4 to 4.44.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4cxw-hq44-r344 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 GHSA-4cxw-hq44-r344 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 GHSA-4cxw-hq44-r344. 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-4cxw-hq44-r344 in your dependencies?
O3 detects GHSA-4cxw-hq44-r344 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.