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PYSEC-2026-1207
aws-sam-cliSummary
The AWS Serverless Application Model Command Line Interface (AWS SAM CLI) is an open-source CLI tool that helps Lambda developers to build and develop Lambda applications locally on their computers using Docker.
When running the AWS SAM CLI build process with Docker and symlinks are included in the build files, the container environment allows a user to access privileged files on the host by leveraging the elevated permissions granted to the tool. A user could leverage the elevated permissions to access restricted files via symlinks and copy them to a more permissive location on the container.
Users should upgrade to v1.133.0 or newer and ensure any forked or derivative code is patched to incorporate the new fixes.
Impact
This issue is limited to the local workspace and does not affect AWS services, production environments or cross-account resources. The issue only affects local workspaces using AWS SAM CLI with container builds (--use-container), potentially allowing access to local files outside the build directory through the usage of symlinks.
Impacted versions: <= AWS SAM CLI v1.132.0
Patches
The issue has been addressed in version 1.133.0. Users should upgrade and ensure any forked or derivative code is patched to incorporate the new fixes. To retain the previous behavior and allow symlinks to resolve on the host machine, please use the explicit '--mount-symlinks' parameter.
Workarounds
There is no recommended work around. Customers are advised to upgrade to version v1.133.0 or the latest version.
References
CVE-2025-3047
If you have any questions or comments about this advisory we ask that you contact AWS/Amazon Security via our vulnerability reporting page or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.
Credit
We would like to thank Kevin Backhouse with the GitHub Security Lab for collaborating on this issue through the coordinated vulnerability disclosure process.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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