CVE-2026-29790 in dbt-common
Summary
by MITRE • 03/06/2026
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.
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Analysis
by VulDB Data Team • 03/14/2026
The vulnerability identified as CVE-2026-29790 resides within dbt-common, a critical component serving as the shared foundation for dbt-core and its various adapter implementations. This utility library handles essential operations including archive extraction processes that are fundamental to dbt's functionality in data transformation and modeling workflows. The flaw specifically targets the safe_extract() function which processes tarball archives, making it a potential entry point for attackers seeking to compromise systems running dbt environments. The vulnerability affects versions prior to 1.34.2 and 1.37.3, indicating a significant window of exposure for organizations relying on these software components.
The technical implementation of the vulnerability stems from the improper use of os.path.commonprefix() within the safe_extract() function. This function was designed to validate that extracted files remain within the intended destination directory by comparing paths using the commonprefix method. However, os.path.commonprefix() operates on a character-by-character comparison rather than component-wise path analysis, creating a fundamental flaw in the validation logic. When processing maliciously crafted tarballs, this approach allows attackers to exploit path traversal by creating archive entries with names that share common prefixes with legitimate directory structures. The vulnerability specifically enables attackers to write files to sibling directories that happen to share matching name prefixes with the target extraction location, bypassing the intended security boundaries.
The operational impact of this vulnerability extends beyond simple path traversal, as it represents a critical security weakness that could enable arbitrary file system modifications within dbt environments. Attackers could potentially leverage this flaw to overwrite critical configuration files, inject malicious code into the data processing pipeline, or establish persistent access points within the target system. This vulnerability is particularly concerning in enterprise environments where dbt is used for sensitive data processing, as it could compromise the integrity of data transformation workflows and potentially lead to data exfiltration or system compromise. The vulnerability's impact is amplified by the widespread adoption of dbt across the data analytics and business intelligence landscape, making it a prime target for exploitation.
Organizations should prioritize immediate remediation by upgrading to dbt-common versions 1.34.2 or 1.37.3, which contain the patched implementation of the safe_extract() function. The fix addresses the core issue by replacing the flawed os.path.commonprefix() approach with proper path component validation that correctly handles directory traversal scenarios. Security teams should also implement monitoring for suspicious archive extraction activities and consider restricting file system permissions for dbt execution environments to limit potential damage from any successful exploitation attempts. This vulnerability aligns with CWE-22 Path Traversal and maps to ATT&CK technique T1059 Command and Scripting Interpreter, highlighting the need for comprehensive security controls around data processing infrastructure. Organizations should also review their broader software supply chain for similar path traversal vulnerabilities in other components that might be vulnerable to the same character-by-character comparison flaw.