CVE-2025-36852 Details

A critical vulnerability allows contributors with pull request privileges to inject compromised artifacts from untrusted environments into trusted production environments. This issue arises in remote cache extensions for common build systems that use bucket-based remote caching, such as those relying on Amazon S3 or Google Cloud Storage. The vulnerability exploits the 'first-to-cache wins' principle, where artifacts from untrusted sources can poison the cache for trusted environments. This cache poisoning occurs during the artifact construction phase, before any security measures like encryption or checksum validation are applied, bypassing traditional security controls and leading to undetectable compromises in production.

There is no effective mitigation for this vulnerability in bucket-based remote cache solutions due to fundamental design limitations. However, if the solution allows it, cache writes from untrusted environments can be disabled, although this may significantly reduce the usefulness of the remote cache.