GHSA-5789-5fc7-67v3
HIGHGHSA-5789-5fc7-67v3 is a high-severity (CVSS 7.1) Path Traversal vulnerability in jupyter-server. O3 Security confirms whether GHSA-5789-5fc7-67v3 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Jupyter Server: Path Traversal via incorrect startswith() root directory check allows access to sibling directories
Blast Radius
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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 | 2.18.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jupyter-server. 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 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 pinpoints whether GHSA-5789-5fc7-67v3 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 GHSA-5789-5fc7-67v3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-5789-5fc7-67v3 in your dependencies?
O3 detects GHSA-5789-5fc7-67v3 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.