NbdimeApplication · Jupyter
CVE-2021-41134
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 · uneditednbdime provides tools for diffing and merging of Jupyter Notebooks. In affected versions a stored cross-site scripting (XSS) issue exists within the Jupyter-owned nbdime project. It appears that when reading the file name and path from disk, the extension does not sanitize the string it constructs before returning it to be displayed. The diffNotebookCheckpoint function within nbdime causes this issue. When attempting to display the name of the local notebook (diffNotebookCheckpoint), nbdime appears to simply append .ipynb to the name of the input file. The NbdimeWidget is then created, and the base string is passed through to the request API function. From there, the frontend simply renders the HTML tag and anything along with it. Users are advised to patch to the most recent version of the affected product.
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
NbdimeApplication
>= 1.0.0, < 1.1.1>= 2.0.0, < 2.1.1>= 3.0.0, <= 3.1.1>= 5.0.0, < 5.0.2>= 6.0.0, < 6.1.2>= 1.0.0, < 1.0.1>= 2.0.0, < 2.1.1CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/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 · scoped1.0.11.1.12.1.1
nbdime >= 5.0.2 (or version 1.1.1 for 1.x, 2.1.1 for 2.x, 3.1.1 for 3.x branch)
- Identify the currently installed nbdime version using: pip show nbdime or pip list | grep nbdime
- For JupyterLab integration, also check nbdime_jupyterlab version: pip show nbdime_jupyterlab
- Upgrade nbdime to the fixed version: pip install --upgrade nbdime>=5.0.2
- If using nbdime_jupyterlab, upgrade it as well: pip install --upgrade nbdime_jupyterlab>=2.1.1
- Restart any running JupyterLab or nbdime servers to ensure the new version is loaded
- Verify the upgrade was successful by checking: pip show nbdime
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-41134 — 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-2021-41134 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
- No weaponised exploit code, or anything meant to cause harm
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