CVE-2024-35225
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedJupyter Server Proxy allows users to run arbitrary external processes alongside their notebook server and provide authenticated web access to them. Versions of 3.x prior to 3.2.4 and 4.x prior to 4.2.0 have a reflected cross-site scripting (XSS) issue. The `/proxy` endpoint accepts a `host` path segment in the format `/proxy/<host>`. When this endpoint is called with an invalid `host` value, `jupyter-server-proxy` replies with a response that includes the value of `host`, without sanitization [2]. A third-party actor can leverage this by sending a phishing link with an invalid `host` value containing custom JavaScript to a user. When the user clicks this phishing link, the browser renders the response of `GET /proxy/<host>`, which runs the custom JavaScript contained in `host` set by the actor. As any arbitrary JavaScript can be run after the user clicks on a phishing link, this issue permits extensive access to the user's JupyterLab instance for an actor. Patches are included in versions 4.2.0 and 3.2.4. As a workaround, server operators who are unable to upgrade can disable the `jupyter-server-proxy` extension.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisUntrusted input is placed into a web page without being neutralised, so an attacker's markup or script executes in another user's browser. That can hijack sessions, capture keystrokes, or silently perform actions as the victim. Fixing it properly means context-aware output encoding everywhere data meets HTML, backed by a content-security policy as a second line of defence.
General guidance for the cross-site scripting (xss) class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 3.0.0, < 3.2.4>= 4.1.2, < 4.2.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped3.2.44.2.0
jupyter-server-proxy 3.2.4 (for 3.x users) or 4.2.0 (for 4.x users)
- Identify your current jupyter-server-proxy version by checking your environment (e.g., pip show jupyter-server-proxy or conda list)
- If using version 3.x (>=3.0.0 and <3.2.4), upgrade to version 3.2.4 using: pip install --upgrade jupyter-server-proxy==3.2.4
- If using version 4.x (>=4.1.2 and <4.2.0), upgrade to version 4.2.0 using: pip install --upgrade jupyter-server-proxy==4.2.0
- If using conda, update with: conda install jupyter-server-proxy=3.2.4 (or 4.2.0 for 4.x users)
- Restart the Jupyter server to apply the upgrade
- Verify the new version is installed and the server starts successfully
Generated from the published advisory — verify against the referenced sources before acting.
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Free · runs locallyCheck whether your project pulls in CVE-2024-35225 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-35225 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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