CVE-2023-43644
CRITICALCVE-2023-43644 is a critical-severity (CVSS 9.1) Missing Authentication vulnerability in github.com/sagernet/sing-box. O3 Security confirms whether CVE-2023-43644 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Improper authentication in the SOCKS5 inbound in sing-box
Real-World Exposure
github.com/sagernet/sing-box🐹github.com/sagernet/sing-box🐹github.com/sagernet/singReal-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
Sing-box is an open source proxy system. Affected versions are subject to an authentication bypass when specially crafted requests are sent to sing-box. This affects all SOCKS5 inbounds with user authentication and an attacker may be able to bypass authentication. Users are advised to update to sing-box 1.4.4 or to 1.5.0-rc.4. Users unable to update should not expose the SOCKS5 inbound to insecure environments.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/sagernet/sing-box | all versions | 1.4.5 |
| 🐹Go | github.com/sagernet/sing-box | ≥ 1.5.0-beta.1&&< 1.5.0-rc.5 | 1.5.0-rc.5 |
| 🐹Go | github.com/sagernet/sing | all versions | 0.2.12-0.20230925092853-5b05b5c147d9 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/sagernet/sing-box. 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/sagernet/sing-box to 1.4.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-43644 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-2023-43644 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-2023-43644. 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-2023-43644 in your dependencies?
O3 detects CVE-2023-43644 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.