{"id":"CVE-2026-29790","aliases":["GHSA-w75w-9qv4-j5xj","PYSEC-2026-2440"],"url":"https://o3.security/vulnerability/CVE-2026-29790","summary":"dbt-common: commonprefix() doesn't protect against path traversal","details":"### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nA path traversal vulnerability exists in dbt-common's `safe_extract()` function used when extracting tarball archives. The function uses `os.path.commonprefix()` to validate that extracted files remain within the intended destination directory. However, `commonprefix()` compares paths character-by-character rather than by path components, allowing a malicious tarball to write files to sibling directories with matching name prefixes.\n\nFor example, when extracting to `/tmp/packages`, a crafted tarball could write files to `/tmp/packagesevil/` by exploiting the character-based prefix matching.\n\nThis vulnerability affects users who:\n- Install dbt packages from untrusted sources\n- Process tarball archives through dbt-common's extraction utilities\n\nThe practical risk is limited because:\n- Exploitation requires a malicious tarball to be processed\n- File writes are restricted to sibling directories with matching prefixes (not arbitrary paths)\n- Packages from trusted sources (dbt Hub) are not affected\n\nThis is similar to CVE-2026-1703 in pip, which had a CVSS score of 3.9 (Low).\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\nFixed in `dbt-common` version 1.37.3 & 1.34.2, and patched for dbt-core 1.11.7 and 1.10.20 releases.\n\nThe fix replaces `os.path.commonprefix()` with `os.path.commonpath()`, which correctly compares paths by their components rather than characters.\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\n- Only install dbt packages from trusted sources (official dbt Hub, verified git repositories)\n- Avoid installing packages from untrusted URLs or unverified third parties\n- Review package contents before installation when sourcing from external locations\n\n### Resources\n_Are there any links users can visit to find out more?_\n\n1. CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'): https://cwe.mitre.org/data/definitions/22.html\n2. CVE-2026-1703 (similar vulnerability in pip): https://nvd.nist.gov/vuln/detail/CVE-2026-1703\n3. pip fix PR #13777: https://github.com/pypa/pip/pull/13777\n4. Python documentation on `commonpath` vs `commonprefix`: https://docs.python.org/3/library/os.path.html#os.path.commonpath","published":"2026-03-06T20:37:42.354Z","modified":"2026-10-28T02:31:07.016960407Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"dbt-common","fixedVersion":"1.34.2"},{"ecosystem":"PyPI","name":"dbt-common","fixedVersion":"1.37.3"}],"fix":{"url":"https://github.com/dbt-labs/dbt-common/commit/e547954a48bac9394ef6eb98432e429dce9a7709","label":"dbt-labs/dbt-common@e547954"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/29xxx/CVE-2026-29790.json"},{"type":"ADVISORY","url":"https://github.com/dbt-labs/dbt-common/security/advisories/GHSA-w75w-9qv4-j5xj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-29790"},{"type":"FIX","url":"https://github.com/dbt-labs/dbt-common/commit/e547954a48bac9394ef6eb98432e429dce9a7709"},{"type":"FIX","url":"https://github.com/pypa/pip/pull/13777"},{"type":"WEB","url":"https://docs.python.org/3/library/os.path.html#os.path.commonpath"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-6vgw-5pg2-w6jp"},{"type":"PACKAGE","url":"https://github.com/dbt-labs/dbt-common"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:31:07.016960407Z"}}