PYSEC-2026-1226

Summary

In affected versions, ingestion paths construct file locations directly from untrusted event_id input without validation. A specially crafted event_id can result in paths outside the intended directory, potentially allowing file overwrite or creation in arbitrary locations.

Submitting such input requires access to a valid DSN. While that limits exposure, DSNs are sometimes discoverable—for example, when included in frontend code—and should not be treated as a strong security boundary.

Impact

A valid DSN holder can craft an event_id that causes the ingestion process to write files outside its designated directory. This allows overwriting files accessible to the user running Bugsink.

If Bugsink runs in a container, the effect is confined to the container’s filesystem. In non-containerized setups, the overwrite may affect other parts of the system accessible to that user.

Mitigation

Update to version 1.7.4, 1.6.4, 1.5.5 or 1.4.3 , which require event_id to be a valid UUID and normalizes it before use in file paths.