Privilege escalation in Fission

CVE-2026-50570

Fission is an open-source, Kubernetes-native serverless framework that simplifies the deployment of functions and applications on Kubernetes. Prior to version 1.25.0, Fission added PodSpec safety validation for tenant-facing Environment and Function CRDs (ValidatePodSpecSafety / ValidateContainerSafety admission webhook + sanitizeContainerSecurityContext executor merge layer), but the capability check was implemented as a fixed denylist of six Linux capabilities (SYS_ADMIN, NET_ADMIN, SYS_PTRACE, SYS_MODULE, DAC_READ_SEARCH, DAC_OVERRIDE). The denylist omitted CAP_SYS_TIME, among others. As a result, a tenant who could create a Function or Environment CRD could request securityContext.capabilities.add: ["SYS_TIME"], pass Fission's admission validation and merge-layer sanitization, and run attacker-controlled code with CAP_SYS_TIME in the resulting function or runtime container. This issue has been patched in version 1.25.0.

Vulnerability class: Privilege Escalation

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L.

EPSS exploit prediction

EPSS: 0.003 (19.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 19.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-50570: held from 0.005 to 0.003.

EPSS over last 30 days · oldest: 0.005 · newest: 0.003 · change: -0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-50570?
CVE-2026-50570 is a high-severity vulnerability in Fission, classified under Improper Privilege Management. CVSS score: 8.5/10. Published 2026-06-10.
How severe is CVE-2026-50570?
High severity. CVSS v3 base score is 8.5 out of 10.