CVE-2026-49823: Fission: Cross-namespace Package read via unvalidated PackageRef in Function admission webhook

Severity: high (CVSS 7.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-10 · updated 2026-06-17
Weakness: CWE-284

Description

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.

Affected products

fission: before 1.24.0

References

https://github.com/fission/fission/pull/3389
https://github.com/fission/fission/releases/tag/v1.24.0
https://github.com/fission/fission/security/advisories/GHSA-3r8v-2xmj-5c39

Get alerted when CVE-2026-49823 or the next vulnerability affects your stack