Answer in brief
CVE-2026-102830 records a Medium severity (CVSS 6.8) vulnerability in JupyterLab: Cross-site scripting (XSS) in JupyterLab via crafted language package (jupyterlab.json). The current sources do not mark it as known exploited. The current feed maps jupyterlab/jupyterlab (generic), jupyterlab/jupyterlite-core (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps jupyterlab/jupyterlab (generic), jupyterlab/jupyterlite-core (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| jupyterlab/jupyterlabgeneric | >=3.0.0 <4.5.11 || >=4.6.0 <4.6.4 | 4.5.11, 4.6.4 |
| jupyterlab/jupyterlite-coregeneric | <0.8.4 | 0.8.4 |
Published upstream
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 29, 2026
JupyterLab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From JupyterLab 3.0.0 until 4.5.11 and 4.6.4, and in JupyterLite Core 0.8.3 and earlier, the Plural-Forms header in a selected third-party language pack can append JavaScript after a valid plural rule because prefix-only regular-expression validation accepts a matching prefix without requiring the entire header to match. JupyterLab passes the accepted expression to new Function, so loading the catalogue and translating a plural string executes the appended code in the authenticated JupyterLab origin. Where Jupyter Server kernels, terminals, and APIs are exposed, the code can use authenticated server APIs to read or modify files and run code. Impact is much more limited in JupyterLite because it typically lacks most exposed Jupyter Server surfaces. The default English locale is unaffected because it does not load a translation catalogue. This issue is fixed in JupyterLab 4.5.11 and 4.6.4 and JupyterLite Core 0.8.4.
Quoted source text, attributed separately from HOL analysis.