CVE-2026-102830: jupyterlab Cross-site Scripting
Vulnerability summary
CVE-2026-102830 is a medium (CVSS 6.8) Cross-site Scripting vulnerability in jupyterlab. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 17.2% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 29-09-2026PublishedVulnerability first disclosed.
- 29-09-2026Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
6 scores · 6 sources · 1 version- OSV · PypiEcosystem advisory · calculated6.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
- OSV · UbuntuEcosystem advisory · calculated6.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
- OSV · DebianEcosystem advisory · calculated6.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
- OSV · ChainguardEcosystem advisory · calculated6.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
- NVDNIST6.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS trend
Probability
0.26%
Chance of exploitation in the next 30 days
Percentile
17%
Versus all other CVEs
30-day change
Change unavailable
Change unavailable
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
- CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Affected systems
Jupyterlab2 products
- jupyterlab≥ 3.0.0, < 4.5.11 | ≥ 4.6.0, < 4.6.4
- jupyterlite-core< 0.8.4
PyPI2 products
- jupyterlab≥ 3.0.0, < 4.5.11 | ≥ 4.6.0, < 4.6.4
- jupyterlite-core< 0.8.4
Chainguard1 product
- jupyterhub-k8s-singleuser-sample< 4.4.2-r7
Debian1 product
- jupyterlabAll versions (No fix recorded)
Ubuntu1 product
- jupyterlabAll versions (No fix recorded)
5 vendors · 7 products
References
15 links- github.com/jupyterlab/jupyterlab/security/advisories/GHSA-3jqq-pw4j-pqcjX Refsource CONFIRMWEBREPORTAdvisory
- github.com/jupyterlab/jupyterlab/commit/985a3223cd77fd4f991cd90066342a90711d70f6X Refsource MISCWEBREPORTFIX
- github.com/jupyterlab/jupyterlab/commit/de324ae91346c713c4f5e5485f97b6e914e0f774X Refsource MISCWEBREPORTFIX
- github.com/jupyterlab/jupyterlab/commit/f9de43dc565a1118120d466117f877a189a4ce90X Refsource MISCWEBREPORTFIX
- pypi.org/project/jupyterlabPACKAGE
