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| Vulnerability ID | VCID-9ch7-su6u-b3ft |
| Aliases |
CVE-2026-40171
GHSA-rch3-82jr-f9w9 |
| Summary | In Jupyter Notebook versions 7.0.0 through 7.5.5, JupyterLab versions 4.5.6 and earlier, and the corresponding @jupyter-notebook/help-extension and @jupyterlab/help-extension packages before 7.5.6 and 4.5.7, a stored cross-site scripting issue in the help command linker can be chained with attacker-controlled notebook content to steal authentication tokens with a single click. An attacker can craft a malicious notebook file containing elements that appear indistinguishable from legitimate controls and trigger execution when a user interacts with them. Successful exploitation allows theft of the user's authentication token and complete takeover of the Jupyter session through the REST API, including reading files, creating or modifying files, accessing kernels to execute arbitrary code, and creating terminals for shell access. This issue has been fixed in Notebook 7.5.6, JupyterLab 4.5.7, @jupyter-notebook/help-extension 7.5.6, and @jupyterlab/help-extension 4.5.7. As a workaround, disable the affected help extensions or set allowCommandLinker to false in the sanitizer configuration. |
| Status | Published |
| Exploitability | None |
| Weighted Severity | None |
| Risk | None |
| Affected and Fixed Packages | Package Details |
| System | Score | Found at |
|---|---|---|
| epss | 0.00059 | https://api.first.org/data/v1/epss?cve=CVE-2026-40171 |
| cvssv4 | 8.4 | https://github.com/jupyter/notebook |
| generic_textual | HIGH | https://github.com/jupyter/notebook |
| cvssv4 | 8.4 | https://github.com/jupyter/notebook/security/advisories/GHSA-rch3-82jr-f9w9 |
| generic_textual | HIGH | https://github.com/jupyter/notebook/security/advisories/GHSA-rch3-82jr-f9w9 |
| ssvc | Track | https://github.com/jupyter/notebook/security/advisories/GHSA-rch3-82jr-f9w9 |
| cvssv4 | 8.4 | https://jupyterlab.readthedocs.io/en/latest/user/commands.html#commands-in-markdown-output-and-files |
| generic_textual | HIGH | https://jupyterlab.readthedocs.io/en/latest/user/commands.html#commands-in-markdown-output-and-files |
| cvssv4 | 8.4 | https://nvd.nist.gov/vuln/detail/CVE-2026-40171 |
| generic_textual | HIGH | https://nvd.nist.gov/vuln/detail/CVE-2026-40171 |
| Attack Vector (AV) | Attack Complexity (AC) | Attack Requirements (AT) | Privileges Required (PR) | User Interaction (UI) | Vulnerable System Impact Confidentiality (VC) | Vulnerable System Impact Integrity (VI) | Vulnerable System Impact Availability (VA) | Subsequent System Impact Confidentiality (SC) | Subsequent System Impact Integrity (SI) | Subsequent System Impact Availability (SA) |
|---|---|---|---|---|---|---|---|---|---|---|
network adjacent local physical |
low high |
none present |
none low high |
none passive active |
high low none |
high low none |
high low none |
high low none |
high low none |
high low none |
| Attack Vector (AV) | Attack Complexity (AC) | Attack Requirements (AT) | Privileges Required (PR) | User Interaction (UI) | Vulnerable System Impact Confidentiality (VC) | Vulnerable System Impact Integrity (VI) | Vulnerable System Impact Availability (VA) | Subsequent System Impact Confidentiality (SC) | Subsequent System Impact Integrity (SI) | Subsequent System Impact Availability (SA) |
|---|---|---|---|---|---|---|---|---|---|---|
network adjacent local physical |
low high |
none present |
none low high |
none passive active |
high low none |
high low none |
high low none |
high low none |
high low none |
high low none |
| Attack Vector (AV) | Attack Complexity (AC) | Attack Requirements (AT) | Privileges Required (PR) | User Interaction (UI) | Vulnerable System Impact Confidentiality (VC) | Vulnerable System Impact Integrity (VI) | Vulnerable System Impact Availability (VA) | Subsequent System Impact Confidentiality (SC) | Subsequent System Impact Integrity (SI) | Subsequent System Impact Availability (SA) |
|---|---|---|---|---|---|---|---|---|---|---|
network adjacent local physical |
low high |
none present |
none low high |
none passive active |
high low none |
high low none |
high low none |
high low none |
high low none |
high low none |
| Attack Vector (AV) | Attack Complexity (AC) | Attack Requirements (AT) | Privileges Required (PR) | User Interaction (UI) | Vulnerable System Impact Confidentiality (VC) | Vulnerable System Impact Integrity (VI) | Vulnerable System Impact Availability (VA) | Subsequent System Impact Confidentiality (SC) | Subsequent System Impact Integrity (SI) | Subsequent System Impact Availability (SA) |
|---|---|---|---|---|---|---|---|---|---|---|
network adjacent local physical |
low high |
none present |
none low high |
none passive active |
high low none |
high low none |
high low none |
high low none |
high low none |
high low none |
| Percentile | 0.18616 |
| EPSS Score | 0.00059 |
| Published At | June 11, 2026, 12:55 p.m. |
| Date | Actor | Action | Source | VulnerableCode Version |
|---|---|---|---|---|
| 2026-06-11T16:53:08.058317+00:00 | Vulnrichment | Import | https://github.com/cisagov/vulnrichment/blob/develop/2026/40xxx/CVE-2026-40171.json | 38.6.0 |