GHSA-gc3j-79f2-7vvw is a high-severity (CVSS 7.7) CWE-284 vulnerability in github.com/fission/fission. A fix is available for github.com/fission/fission — see the affected versions and patch details below.
Fission: Cross-namespace event leakage via KubernetesWatchTrigger allows persistent tenant surveillance
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-gc3j-79f2-7vvw by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 380,066 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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
A low-privilege developer who could create a KubernetesWatchTrigger (KWT) in their own namespace was able to establish a persistent surveillance channel over any other namespace.
Details
Two independent flaws compounded:
pkg/kubewatcher/kubewatcher.go::createKubernetesWatchusedw.Spec.Namespace(user-controlled) directly as the Watch target without checking it againstw.Namespace(the KWT's own namespace).kubewatcherestablished the Watch using its cluster-scoped service account and serialized every Pod/Service/Job change event as full JSON over HTTP POST to the attacker's function.- The validating webhook (
pkg/webhook/kuberneteswatchtrigger.go) registeredverbs=createonly, soupdate/patchrequests bypassed validation entirely.
A separate leak: an empty spec.namespace resolved to all namespaces via the controller's default, letting an attacker omit the field to surveil the entire cluster.
Impact
A tenant with kuberneteswatchtriggers.fission.io/create could continuously receive full event payloads for Pods, Services, and Jobs in any namespace — a persistent cross-tenant surveillance channel requiring no additional privileges.
Fix
Fixed in #3379 and released in v1.24.0.
- The validating webhook marker is extended to
verbs=create;update. ValidaterejectsKubernetesWatchTrigger.spec.namespace != metadata.namespace.- A controller guard in
createKubernetesWatchrejects cross-namespace targets that bypass admission and coerces an emptySpec.Namespaceto the trigger's own namespace.
Behavioural change
KubernetesWatchTriggers with an unset spec.namespace now watch only their own namespace instead of all namespaces. Anyone relying on the previous all-namespaces behaviour must create a separate KWT per namespace.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fission/fission | all versions | 1.24.0go get github.com/fission/fission@v1.24.0 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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-gc3j-79f2-7vvw is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is GHSA-gc3j-79f2-7vvw in your dependencies?
Find it across Go, including transitive dependencies.