GHSA-8wcj-mfrc-jx5q
MEDIUMFission builder pods auto-mount the fission-builder ServiceAccount token in the user-supplied builder container
Blast Radius
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Description
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 and released in v1.24.0. In createBuilderDeployment:
- Set pod-level
AutomountServiceAccountToken=falseon the initial PodSpec and add the projected fetcher SA-token volume. - Re-clamp
AutomountServiceAccountToken=falseafter everyMergePodSpeccall 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fission/fission | all versions | 1.24.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/fission/fission. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/fission/fission to 1.24.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8wcj-mfrc-jx5q is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-8wcj-mfrc-jx5q is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-8wcj-mfrc-jx5q. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-8wcj-mfrc-jx5q in your dependencies?
O3 detects GHSA-8wcj-mfrc-jx5q across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.