CVE-2023-39966 — 1Panel
HIGHCVE-2023-39966 is a high-severity (CVSS 7.5) CWE-862 vulnerability in github.com/1Panel-dev/1Panel. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for github.com/1Panel-dev/1Panel — see the affected versions and patch details below.
1Panel arbitrary file write vulnerability exists in the background
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-39966.
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/1Panel-dev/1PanelReal-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
Summary
An arbitrary file write vulnerability could lead to direct control of the server
Details
Arbitrary file creation
In the api/v1/file.go file, there is a function called SaveContentthat,It recieves JSON data sent by users in the form of a POST request. And the lack of parameter filtering allows for arbitrary file write operations.It looks like this:
- Vulnerable Code
PoC
- We can write the SSH public key into the /etc/.root/authorized_keys configuration file on the server.
-
The server was successfully written to the public key
-
Successfully connected to the target server using an SSH private key.
As a result, the server is directly controlled, causing serious harm
Impact
1Panel v1.4.3
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/1Panel-dev/1Panel | ≥ 1.4.3&&< 1.5.0 | 1.5.0go get github.com/1Panel-dev/1Panel@v1.5.0 |
Affected Products
1panelfit2cloudResearch 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/1Panel-dev/1Panel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/1Panel-dev/1Panel to 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-39966 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-2023-39966 in your dependencies?
Find it across Go, including transitive dependencies.