GHSA-5789-5fc7-67v3 — jupyter-server
HIGHGHSA-5789-5fc7-67v3 is a high-severity (CVSS 7.1) Path Traversal vulnerability in jupyter-server. A fix is available for jupyter-server — see the affected versions and patch details below.
Jupyter Server: Path Traversal via incorrect startswith() root directory check allows access to sibling directories
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 GHSA-5789-5fc7-67v3.
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
GHSA-5789-5fc7-67v3 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 377,636 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
jupyter-serverReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Jupyter Server <=2.17.0 can access directories sibling to the root directory, if it starts with the root dir's name.
PoC
Minimal:
.
├── test/ <- root directory.
│ └── test.txt
└── testtest/
└── secret.txt <- file to exfiltrate that we should not be able to access via API
HOST="http://localhost:8888"
TOKEN=""
SIBLING="testtest"
TARGET="secret.txt"
curl -s -X POST \
"$HOST/api/contents/%2e%2e/$SIBLING/$TARGET/checkpoints" \
-H "Authorization: token $TOKEN"
Full PoC by @stef41: https://gist.github.com/Yann-P/66d4982a965dee8fcb8dd89db29e7006
Impact
It is possible for an authenticated user to access content outside the server's root_dir in siblings directories sharing the same prefix as the root_dir. The attacker can escalate access, reading, writing, and deleting from sibling directories.
This can have a tangible impact for deployments using predictable naming scheme with multi-tenant server, for example user1, user2, user3, ..., user10 etc, as user1 could access and modify files of all user10 - user19 and higher.
In a hypothetical system where users can choose a name of their folder, an attacker could choose a single-letter username to gain access to a significant number of sibling directories.
Workarounds
Use folder names that do not overlap.
Acknowledgments
Thank you to @stef41 for providing a useful PoC.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | jupyter-server | all versions | 2.18.0pip install --upgrade 'jupyter-server==2.18.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jupyter-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update jupyter-server to 2.18.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5789-5fc7-67v3 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 GHSA-5789-5fc7-67v3 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-5789-5fc7-67v3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This Important flaw in Jupyter Server enables an authenticated user to bypass their configured root directory via a path traversal vulnerability in the REST API. This allows access to, and manipulation of, files within sibling directories that share a common prefix. The risk is elevated in multi-tenant Red Hat…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Migration Toolkit for Applications 8.2 | mta/mta-solution-server-rhel9:1784109883 | RHSA-2026:43038 |
| Red Hat OpenShift AI 3.4 | rhoai/odh-th06-cpu-torch210-py312-rhel9:1787076778 | RHSA-2026:60520 |
Frequently Asked Questions
Is GHSA-5789-5fc7-67v3 in your dependencies?
O3 Security finds GHSA-5789-5fc7-67v3 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.