EUVD-2026-36096
GHSA-3r8v-2xmj-5c39
Severity by source
AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Primary rating from Vendor (GitHub_M).
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Lifecycle Timeline
3DescriptionNVD
Fission is an open-source, Kubernetes-native serverless framework that simplifies the deployment of functions and applications on Kubernetes. Prior to version 1.24.0, a Fission Function spec carries three reference types - Secret, ConfigMap, and Package. The first two were namespace-validated by the admission webhook; PackageRef.Namespace was not. This issue has been patched in version 1.24.0.
Articles & Coverage 1
AnalysisAI
Cross-namespace access control bypass in Fission prior to 1.24.0 allows an authenticated tenant to reference Package objects belonging to other Kubernetes namespaces because the admission webhook validated namespaces for Secret and ConfigMap references but omitted the equivalent check for PackageRef.Namespace. A low-privileged user with rights to create Function objects in their own namespace can therefore reach Package contents in arbitrary namespaces, producing a scope-changing confidentiality breach (CVSS 7.7, S:C, C:H). No public exploit identified at time of analysis; not listed in CISA KEV.
Technical ContextAI
Fission is a Kubernetes-native serverless framework where Function custom resources tie together three reference types - Secret, ConfigMap, and Package - each carrying a Name plus a Namespace. The fix in PR #3389 (pkg/webhook/function.go) shows the admission webhook previously validated cross-namespace use for Environment and the other refs but never compared PackageRef.Namespace against the Function's own namespace, the classic CWE-284 (Improper Access Control) tenancy-boundary failure. Because Fission's executor types (newdeploy/newdeploymgr.go and poolmgr/gpm.go) resolve the referenced Package server-side using controller-level credentials, a namespace value supplied by the tenant is honored without RBAC re-checking, which is why a Function in namespace A can dereference a Package in namespace B. The patch adds reject-on-mismatch logic in the admission webhook plus defense-in-depth checks in both executor paths to cover stale objects from a failurePolicy=ignore window - the empty-namespace case is intentionally still accepted because the Fission CLI populates it with the function's own namespace.
RemediationAI
Vendor-released patch: upgrade Fission to v1.24.0 or later (https://github.com/fission/fission/releases/tag/v1.24.0), which adds the missing PackageRef.Namespace check inside the admission webhook (pkg/webhook/function.go) and mirrored defense-in-depth checks in the newdeploy and poolmgr executors. If immediate upgrade is not possible, audit existing Function objects across all namespaces for any Spec.Package.PackageRef.Namespace value that differs from the parent Function's namespace and delete or rewrite them; this is detective rather than preventive and will not stop new attempts. As a compensating control, restrict who can create or update Function custom resources via Kubernetes RBAC so only trusted operators (not shared tenants) hold the verb, accepting the trade-off that this defeats Fission's self-service tenancy model. Confirm the admission webhook is installed with failurePolicy=Fail rather than Ignore so that webhook downtime does not silently permit cross-namespace references during the upgrade window.
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Same weakness CWE-284 – Improper Access Control
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View allVendor StatusVendor
SUSE
Severity: Important| Product | Status |
|---|---|
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Affected |
| openSUSE Leap 15.5 | Affected |
| openSUSE Leap 15.6 | Affected |
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