JupyterLab Git: Stored XSS leading to RCE

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

JupyterLab Git is a Git extension for JupyterLab. From 0.30.0b3 before 0.54.0, the PlainTextDiff.ts createHeader() method passes Git filenames directly to innerHTML when rendering renamed files in commit history, allowing a crafted filename to execute JavaScript when a victim views the rename diff in the Git History tab. This issue is fixed in version 0.54.0.

Source published

8 Jul 2026 21:03:01 UTC

Source modified

9 Jul 2026 14:16:09 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

JupyterLab Git is a Git extension for JupyterLab. From 0.30.0b3 before 0.54.0, the PlainTextDiff.ts createHeader() method passes Git filenames directly to innerHTML when rendering renamed files in commit history, allowing a crafted filename to execute JavaScript when a victim views the rename diff in the Git History tab. This issue is fixed in version 0.54.0.

Source published

Jul 8, 2026, 9:03:01 PM (timezone not stated)

Source modified

Jul 9, 2026, 2:16:09 PM (timezone not stated)

Observed here

7 Nov 2026 12:30:05 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

JupyterLab Git is a Git extension for JupyterLab. From 0.30.0b3 before 0.54.0, the PlainTextDiff.ts createHeader() method passes Git filenames directly to innerHTML when rendering renamed files in commit history, allowing a crafted filename to execute JavaScript when a victim views the rename diff in the Git History tab. This issue is fixed in version 0.54.0.

Source published

8 Jul 2026 21:16:49 UTC

Source modified

25 Oct 2026 17:10:00 UTC

Observed here

27 Oct 2026 14:13:32 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 9.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Overview Amazon Web Services (AWS) Security has identified a stored cross-site scripting (XSS) issue in the jupyterlab-git JupyterLab extension that can lead to remote code execution (RCE). The issue exists in the PlainTextDiff.ts component, where the createHeader() method passes Git filenames directly to innerHTML without sanitization when rendering diffs for renamed files in commit history. This allows an adversary to craft a filename containing arbitrary HTML/JavaScript that executes when another user views the rename diff in the Git History tab. The issue can be leveraged through the rename history view in the JupyterLab Git panel. An adversary creates a file with a crafted filename containing a JavaScript payload (e.g., <img src=x onerror=eval(atob("base64_payload"))>.py), renames the file in a subsequent commit, and pushes to a shared repository. When a victim clones the repository, navigates to the Git History tab, clicks the rename commit, and then clicks the renamed file to view the diff, the unsanitized filename renders via innerHTML, executing arbitrary JavaScript in the victim's browser session. The injected JavaScript reads the xsrf cookie, opens a JupyterLab terminal via POST /api/terminals, connects via WebSocket, and executes arbitrary shell commands — achieving full RCE. An adversary can leverage this to exfiltrate secrets or credentials from the victim's environment. Scope of impact We discovered this issue during internal security testing. The issue is present in the default configuration of JupyterLab when the jupyterlab-git extension is installed. The attack requires: - The adversary to have commit access to a Git repository that the victim has cloned - The victim to navigate to the Git History tab, click the rename commit, and click the renamed file to view the diff The issue could allow an actor who has access to a shared Git repository to execute arbitrary JavaScript in another user's JupyterLab environment by committing a file with a crafted filename, potentially leading to remote code execution with access to user code, data, environment variables, and credentials. Proof of concept The issue exists in the createHeader() method where filenames from rename history are passed directly to innerHTML without sanitization: [1] https://github.com/jupyterlab/jupyterlab-git/blob/main/src/components/diff/PlainTextDiff.ts#L214 Attack flow: 1. An adversary creates a file with a crafted filename containing a JavaScript payload, e.g., <img src=x onerror=eval(atob("base64_payload"))>.py 2. The adversary renames the file in a subsequent commit and pushes both commits to a shared Git repository 3. The victim clones or pulls the repository and navigates to the Git History tab in JupyterLab 4. The victim clicks the rename commit, then clicks the renamed file to view the diff 5. The createHeader() method constructs a diff header using string concatenation with the unsanitized filename and assigns the result to innerHTML 6. The injected JavaScript executes in the victim's browser session, reads the _xsrf cookie, sends a POST request to /api/terminals to open a JupyterLab terminal, connects via WebSocket, and executes arbitrary shell commands Proof-of-concept mitigation The issue can be mitigated by replacing innerHTML with textContent for filename rendering in the createHeader() method of PlainTextDiff.ts. Alternatively, proper HTML sanitization (escaping <, >, &, ", ') can be applied before inserting user-controlled filenames into the DOM.

Source published

19 Jun 2026 19:36:04 UTC

Source modified

4 Sep 2026 21:30:06 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Publisher rating · HIGH