GHSA-8wcj-mfrc-jx5q is a medium-severity (CVSS 4.9) CWE-250 vulnerability in github.com/fission/fission. O3 Security confirms whether GHSA-8wcj-mfrc-jx5q is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Fission builder pods auto-mount the fission-builder ServiceAccount token in the user-supplied builder container
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-8wcj-mfrc-jx5q.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-8wcj-mfrc-jx5q plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/fission/fissionReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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.