An issue was discovered in the Dask distributed package before 2021.10.0 for Python.
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
| — | distributed (PyPI) | before 2021.10.0 | 2021.10.0 | Patch available | GHSA-hwqr-f3v9-hwxr |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
- distributed (PyPI) Vendor— Affected before 2021.10.0 Fixed in 2021.10.0 Patch available GHSA-hwqr-f3v9-hwxr
Remediation
- Fix · GHSA-hwqr-f3v9-hwxr distributed (PyPI) Fixed in 2021.10.0 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-42343
- 2026-10-03 Alias added: GHSA-hwqr-f3v9-hwxr
References
Advisory 4
Other 5
- https://github.com/dask/distributed/pull/5427
- https://github.com/dask/distributed/commit/afce4be8e05fb180e50a9d9e38465f1a82295e1b
- https://github.com/dask/distributed
- https://github.com/pypa/advisory-database/tree/main/vulns/distributed/PYSEC-2021-871.yaml
- https://github.com/pypa/advisory-database/tree/main/vulns/distributed/PYSEC-2021-872.yaml
More Anaconda Dask vulnerabilities
- TI-2026-18952 Dask distributed Vulnerable to Remote Code Execution via Jupyter Proxy and Dashboard CVSS 4.0MEDIUM 5.3
Sources
- CVE-2021-42343 · CVE Program
- CVE-2021-42343 · NVD
- FIRST EPSS
- GHSA-hwqr-f3v9-hwxr · GitHub Advisory Database · CC BY 4.0
- CVE-2021-42343 · Red Hat security data · CC BY 4.0
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