How severe is CVE-2023-39966?

CVE-2023-39966 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-39966?

CVE-2023-39966 affects the following packages: github.com/1Panel-dev/1Panel (Go). Ecosystems affected: Go.

How do I fix CVE-2023-39966?

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.

How do I detect CVE-2023-39966 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/1Panel-dev/1Panel. 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.

How do I mitigate CVE-2023-39966 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2023-39966?

O3 pinpoints whether CVE-2023-39966 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2023-39966 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2023-39966, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-39966?

CVE-2023-39966 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 48th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-39966?

CVE-2023-39966 is classified as CWE-862 (CWE-862). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-39966 published, and has it been updated?

CVE-2023-39966 was published on August 10, 2023 and was last updated on March 14, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

CVE-2023-39966

HIGH

1Panel arbitrary file write vulnerability exists in the background

Also known asGHSA-hf7j-xj3w-87g4GO-2023-2006

Published

Aug 10, 2023

Updated

Mar 14, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk48th percentile+0.47%

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.

Blast Radius

1 pkg affected

🐹github.com/1Panel-dev/1Panel

Real-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

1Panel is an open source Linux server operation and maintenance management panel. In version 1.4.3, an arbitrary file write vulnerability could lead to direct control of the server. 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. Version 1.5.0 contains a patch for this issue.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/1Panel-dev/1Panel`	≥ 1.4.3&&< 1.5.0	1.5.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

1Panel is an open source Linux server operation and maintenance manageme…

github.comNVDAug 2023

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/1Panel-dev/1Panel. 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/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
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-2023-39966 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-2023-39966. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

1Panel is an open source Linux server operation and maintenance management panel. In version 1.4.3, an arbitrary file write vulnerability could lead to direct control of the server. 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. Version 1.5.0 contains a patch for this issue.

O3 Security · Impact-Aware SCA

Is CVE-2023-39966 in your dependencies?

O3 detects CVE-2023-39966 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works