GHSA-8wcj-mfrc-jx5q
Fission builder pods auto-mount the fission-builder ServiceAccount token in the user-supplied builder container
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/fission/fission | < 1.24.0 | 1.24.0 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Summary
Fission builder pods were created with `ServiceAccountName: fission-builder` and no `AutomountServiceAccountToken: false`, so the kubelet auto-mounted the service-account token into every container in the pod — including the
user-supplied builder image.
### Details
The user controls the builder container image, command, and podspec through `Environment.spec.builder.image` / `.container` / `.podspec`. With the SA token auto-mounted at `/var/run/secrets/kubernetes.io/serviceaccount/token` inside that
container, any code running there inherited the `fission-builder` identity. The `fission-builder` SA holds namespace-wide `get` on `secrets` and `configmaps` (`pkg/utils/serviceaccount.go`), so the user-controlled builder container
could read every Secret in the builder namespace by name.
This is the buildermgr sibling of GHSA-85g2-pmrx-r49q (CVE-2026-46617), whose fix suppressed the SA-token automount on function runtime pods but did not cover the structurally identical primitive in `pkg/buildermgr/envwatcher.go`.
### Impact
A subject with `create`/`update` on `Environment` CRDs in a namespace observed by the buildermgr could read every Secret and ConfigMap in the builder namespace via the auto-mounted `fission-builder` token.
### Fix
Fixed in [#3390](https://github.com/fission/fission/pull/3390) and released in [v1.24.0](https://github.com/fission/fission/releases/tag/v1.24.0). In `createBuilderDeployment`:
- Set pod-level `AutomountServiceAccountToken=false` on the initial PodSpec and add the projected fetcher SA-token volume.
- Re-clamp `AutomountServiceAccountToken=false` after every `MergePodSpec` call so a user-supplied podspec cannot restore the kubelet automount.
- Mount the token via a projected volume on the fetcher sidecar only, so the legitimate build → archive-upload flow keeps its cluster API access.
Reuses the projected-volume helpers from `pkg/executor/util/satoken.go` introduced by the GHSA-85g2-pmrx-r49q fix.
### Behavioural change
The user-supplied builder container no longer receives an auto-mounted SA token. The fetcher sidecar still gets its token via a projected volume.
References
External links from the advisory. They lead to third-party sites.
- https://github.com/fission/fission/security/advisories/GHSA-8wcj-mfrc-jx5q
- https://nvd.nist.gov/vuln/detail/CVE-2026-50565
- https://github.com/fission/fission/pull/3390
- https://github.com/fission/fission/commit/8fa799417c77ce8a0189d9858bfe11ece29b84a6
- https://github.com/fission/fission
- https://github.com/fission/fission/releases/tag/v1.24.0