CVE-2023-30626 is a high-severity (CVSS 8.8) Path Traversal vulnerability in Jellyfin.Controller. 2 public exploit references exist, so weaponization risk is real. A fix is available for Jellyfin.Controller — see the affected versions and patch details below.
Jellyfin vulnerable to directory traversal and file write causing arbitrary code execution
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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-2023-30626.
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-2023-30626 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 377,166 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
Jellyfin.ControllerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Jellyfin is a free-software media system. Versions starting with 10.8.0 and prior to 10.8.10 and prior have a directory traversal vulnerability inside the ClientLogController, specifically /ClientLog/Document. When combined with a cross-site scripting vulnerability (CVE-2023-30627), this can result in file write and arbitrary code execution. Version 10.8.10 has a patch for this issue. There are no known workarounds.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Jellyfin.Controller | ≥ 10.8.0&&< 10.8.10 | 10.8.10dotnet add package Jellyfin.Controller --version 10.8.10 |
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 Jellyfin.Controller, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Jellyfin.Controller to 10.8.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-30626 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-2023-30626 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-30626. 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-2023-30626 in your dependencies?
O3 Security finds CVE-2023-30626 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.