PYSEC-2026-2440
Vulnerability from pysec - Published: 2026-07-13 14:36 - Updated: 2026-07-13 16:03Impact
What kind of vulnerability is it? Who is impacted?
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.
For example, when extracting to /tmp/packages, a crafted tarball could write files to /tmp/packagesevil/ by exploiting the character-based prefix matching.
This vulnerability affects users who: - Install dbt packages from untrusted sources - Process tarball archives through dbt-common's extraction utilities
The practical risk is limited because: - Exploitation requires a malicious tarball to be processed - File writes are restricted to sibling directories with matching prefixes (not arbitrary paths) - Packages from trusted sources (dbt Hub) are not affected
This is similar to CVE-2026-1703 in pip, which had a CVSS score of 3.9 (Low).
Patches
Has the problem been patched? What versions should users upgrade to?
Fixed in dbt-common version 1.37.3 & 1.34.2, and patched for dbt-core 1.11.7 and 1.10.20 releases.
The fix replaces os.path.commonprefix() with os.path.commonpath(), which correctly compares paths by their components rather than characters.
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
- Only install dbt packages from trusted sources (official dbt Hub, verified git repositories)
- Avoid installing packages from untrusted URLs or unverified third parties
- Review package contents before installation when sourcing from external locations
Resources
Are there any links users can visit to find out more?
- CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'): https://cwe.mitre.org/data/definitions/22.html
- CVE-2026-1703 (similar vulnerability in pip): https://nvd.nist.gov/vuln/detail/CVE-2026-1703
- pip fix PR #13777: https://github.com/pypa/pip/pull/13777
- Python documentation on
commonpathvscommonprefix: https://docs.python.org/3/library/os.path.html#os.path.commonpath
| Name | purl | dbt-common | pkg:pypi/dbt-common |
|---|
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "dbt-common",
"purl": "pkg:pypi/dbt-common"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.34.2"
},
{
"introduced": "1.35.0"
},
{
"fixed": "1.37.3"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.1.0",
"0.1.0a1",
"0.1.1",
"0.1.3",
"0.1.4",
"0.1.5",
"0.1.6",
"1.0.0",
"1.0.0b1",
"1.0.0b2",
"1.0.1",
"1.0.2",
"1.0.3",
"1.0.4",
"1.1.0",
"1.10.0",
"1.11.0",
"1.12.0",
"1.13.0",
"1.14.0",
"1.15.0",
"1.16.0",
"1.17.0",
"1.18",
"1.19",
"1.2.0",
"1.20",
"1.21.0",
"1.22.0",
"1.23.0",
"1.24.0",
"1.25.0",
"1.25.1",
"1.26.0",
"1.27.0",
"1.27.1",
"1.28.0",
"1.29.0",
"1.3.0",
"1.30.0",
"1.31.0",
"1.32.0",
"1.33.0",
"1.34.0",
"1.34.1",
"1.35.0",
"1.36.0",
"1.37.0",
"1.37.1",
"1.37.2",
"1.4.0",
"1.5.0",
"1.6.0",
"1.7.0",
"1.8.0",
"1.9.0"
]
}
],
"aliases": [
"CVE-2026-29790",
"GHSA-w75w-9qv4-j5xj"
],
"details": "### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nA path traversal vulnerability exists in dbt-common\u0027s `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\u0027s 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 \u0026 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 (\u0027Path Traversal\u0027): 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",
"id": "PYSEC-2026-2440",
"modified": "2026-07-13T16:03:50.863034Z",
"published": "2026-07-13T14:36:40.777932Z",
"references": [
{
"type": "WEB",
"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": "WEB",
"url": "https://github.com/pypa/pip/pull/13777"
},
{
"type": "WEB",
"url": "https://github.com/dbt-labs/dbt-common/commit/e547954a48bac9394ef6eb98432e429dce9a7709"
},
{
"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"
},
{
"type": "PACKAGE",
"url": "https://pypi.org/project/dbt-common"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-w75w-9qv4-j5xj"
}
],
"severity": [
{
"score": "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",
"type": "CVSS_V4"
}
],
"summary": "dbt-common\u0027s commonprefix() doesn\u0027t protect against path traversal"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.