Executive brief
Fission is a framework for running serverless functions on Kubernetes. A security flaw allowed a user in one project area (namespace) to access the source code and sensitive credentials of functions belonging to other projects. This could lead to the theft of intellectual property or the exposure of passwords and API keys used by other teams within the same cluster.
Technical details
A vulnerability in the Fission Function admission webhook exists due to missing namespace validation for 'PackageRef.Namespace'. An attacker with permissions to create functions in their own namespace can specify a 'PackageRef' pointing to a different namespace. When the function is invoked, the 'fission-fetcher' service account—which possesses cluster-wide 'get packages' permissions—retrieves the target package and writes its contents to the attacker's pod. This allows for the extraction of deployment archives, source code, and embedded secrets from any package in the cluster. The issue is fixed in version 1.24.0 by enforcing that the package namespace matches the function's metadata namespace.
Affected products
- fission fission <= 1.23.0
Timeline
- 2026-05-26: disclosed
- 2026-06-10: kev added: NVD Published Date
- 2026-06-30: advisory: GitHub Advisory published/reviewed
- 1.24.0: patched