{"cve":"CVE-2021-42343","nvd":{"published":"2021-10-26T11:15:07.800","modified":"2026-06-17T04:09:40.847","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":[],"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"],"products":["anaconda:dask"],"source":"nvd","synced_at":"2026-10-19T21:24:39.218183596+00:00"},"epss":{"cve":"CVE-2021-42343","score":0.02982,"percentile":0.87293,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-hwqr-f3v9-hwxr","url":"https://osv.dev/vulnerability/GHSA-hwqr-f3v9-hwxr","summary":"Workers for local Dask clusters mistakenly listened on public interfaces","modified":"2026-07-09T16:56:37.896815557Z","packages":[{"ecosystem":"PyPI","name":"distributed","purl":"pkg:pypi/distributed","ranges":["<2021.10.0"],"fixed":["2021.10.0"]}]},{"id":"PYSEC-2021-387","url":"https://osv.dev/vulnerability/PYSEC-2021-387","summary":"","modified":"2026-07-09T16:56:37.896815557Z","packages":[{"ecosystem":"PyPI","name":"dask","purl":"pkg:pypi/dask","ranges":["<2021.10.0"],"fixed":["2021.10.0"]}]},{"id":"PYSEC-2021-871","url":"https://osv.dev/vulnerability/PYSEC-2021-871","summary":"","modified":"2026-07-09T16:56:37.896815557Z","packages":[{"ecosystem":"PyPI","name":"distributed","purl":"pkg:pypi/distributed","ranges":["<2021.10.0"],"fixed":["2021.10.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}