CVE-2023-43644 is a critical-severity (CVSS 9.1) Missing Authentication vulnerability in github.com/sagernet/sing-box. A fix is available for github.com/sagernet/sing-box — see the affected versions and patch details below.
Improper authentication in the SOCKS5 inbound in sing-box
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- 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 CVE-2023-43644.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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 | 1.4.5go get github.com/sagernet/sing-box@v1.4.5 |
| 🐹Go | github.com/sagernet/sing-box | ≥ 1.5.0-beta.1&&< 1.5.0-rc.5 | 1.5.0-rc.5go get github.com/sagernet/sing-box@v1.5.0-rc.5 |
| 🐹Go | github.com/sagernet/sing | all versions | 0.2.12-0.20230925092853-5b05b5c147d9go get github.com/sagernet/sing@v0.2.12-0.20230925092853-5b05b5c147d9 |
Affected Products
sing-boxsagernetDetection & 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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2023-43644 in your dependencies?
Find it across Go, including transitive dependencies.