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CVE-2026-81838 - Zip Slip path traversal in awsdac (diagram-as-code)

Bulletin ID: 2026-090-AWS
Scope: AWS
Content Type: Important (requires attention)
Publication Date: 08/27/2026 13:00 PM PDT

Description:

awsdac (diagram-as-code) is a CLI tool that generates AWS architecture diagrams from YAML definitions, enabling version-controlled, code-driven diagramming. We identified CVE-2026-81838, a Zip Slip (path traversal) issue. When awsdac extracts a zip archive referenced by a ZipFile resource in a definition file, a crafted archive can write files outside the intended cache directory, to any path writable by the user running awsdac. Depending on the file written, this can lead to arbitrary code execution.

Leveraging this issue requires processing a definition file from an untrusted source. This can occur when:

  • awsdac is run without definition trust restrictions (versions prior to 0.22.4 had no trust distinction; version 0.22.4 and later require the --allow-untrusted-definitions flag), or
  • a definition file is loaded from the local filesystem (`Type: LocalFile`), which bypasses the definition URL allowlist.

CI/CD environments that process definition files from untrusted or semi-trusted sources are the primary risk scenario.

awsdac is a client-side CLI tool that renders architecture diagrams locally. This issue does not affect any AWS service, AWS account, or customer data. The impact is limited to the machine on which awsdac runs.

Impacted versions: awsdac: versions 0.10 through 0.23 (inclusive)

Resolution:

This issue has been addressed in version 0.24. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Workarounds:

If you cannot upgrade immediately:

  • Only process definition files (including local files) from sources you trust.
  • Do not run awsdac with the --allow-untrusted-definitions flag (version 0.22.4 and later).
  • In CI/CD pipelines, pin the definition files consumed by awsdac to reviewed, trusted content.

References:

Acknowledgement:

We would like to thank George Chen for collaborating on this issue through the coordinated vulnerability disclosure process.


Please email aws-security@amazon.com with any security questions or concerns.