CVE-2023-36821 is a high-severity (CVSS 8.8) Improper Input Validation vulnerability in uptime-kuma. 1 public exploit reference exists, so weaponization risk is real. A fix is available for uptime-kuma — see the affected versions and patch details below.
Uptime Kuma vulnerable to authenticated remote code execution via malicious plugin installation
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.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-36821.
EPSS Exploitation Probability
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.
How urgent is this, really
CVE-2023-36821 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
uptime-kumanpmDescription
Uptime Kuma, a self-hosted monitoring tool, allows an authenticated attacker to install a maliciously crafted plugin in versions prior to 1.22.1, which may lead to remote code execution. Uptime Kuma allows authenticated users to install plugins from an official list of plugins. This feature is currently disabled in the web interface, but the corresponding API endpoints are still available after login. After downloading a plugin, it's installed by calling npm install in the installation directory of the plugin. Because the plugin is not validated against the official list of plugins or installed with npm install --ignore-scripts, a maliciously crafted plugin taking advantage of npm scripts can gain remote code execution. Version 1.22.1 contains a patch for this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | uptime-kuma | all versions | 1.22.1npm install uptime-kuma@1.22.1 |
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 uptime-kuma, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update uptime-kuma to 1.22.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-36821 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-36821 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-36821. 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-2023-36821 in your dependencies?
O3 Security finds CVE-2023-36821 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.