What’s Vulnerable › Vulnerabilities

CVE-2021-42343

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-26 · updated 2026-06-17

Description

An issue was discovered in the Dask distributed package before 2021.10.0 for Python. Single machine Dask clusters started with dask.distributed.LocalCluster or dask.distributed.Client (which defaults to using LocalCluster) would mistakenly configure their respective Dask workers to listen on external interfaces (typically with a randomly selected high port) rather than only on localhost. A Dask cluster created using this method (when running on a machine that has an applicable port exposed) could be used by a sophisticated attacker to achieve remote code execution.

Affected products

• Anaconda Dask: before 2021.10.0 — fixed in 2021.10.0

How to fix

Upgrade to a fixed version: Anaconda Dask 2021.10.0. Check the vendor advisory for mitigations.

References

• https://docs.dask.org/en/latest/changelog.html
• https://github.com/dask/dask/tags
• https://github.com/dask/distributed/security/advisories/GHSA-hwqr-f3v9-hwxr
• https://docs.dask.org/en/latest/changelog.html
• https://github.com/dask/dask/tags
• https://github.com/dask/distributed/security/advisories/GHSA-hwqr-f3v9-hwxr

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