What is the CVSS score of CVE-2026-50570?

CVE-2026-50570 has a CVSS 3.1 base score of 8.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L. EPSS exploitation probability: 0.0%.

Which versions of Fission are affected by CVE-2026-50570?

Fission (Kubernetes serverless framework) versions prior to 1.25.0 contain a privilege escalation vulnerability allowing authenticated tenants with CRD creation permissions to bypass admission…. A patch is available.

How to fix or mitigate CVE-2026-50570?

Within 24 hours: Identify all Fission deployments and determine their current versions; prioritize environments with untrusted or semi-trusted tenants. Within 7 days: Restrict Function and Environment CRD creation to authorized administrative users only via RBAC; deploy Pod Security Policies or Pod Security Standards to enforce comprehensive Linux capability denylists that block CAP_SYS_TIME and other non-essential capabilities. Within 30 days: Monitor upstream Fission releases for version 1.25.0 or later patch availability; test and deploy patch immediately upon release; conduct audit of all CRD modifications and function executions from before mitigations were applied.

Fission CVE-2026-50570

EUVD-2026-36074 HIGH

Improper Privilege Management (CWE-269)

2026-06-10 GitHub_M

GHSA-qf5v-m7p4-95rp

Privilege Escalation Kubernetes Suse Fission

8.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.5 HIGH

AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L

SUSE

HIGH

qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

High

Availability

Low

Lifecycle Timeline

Patch available

Jun 10, 2026 - 20:01 EUVD

Source Code Evidence Fetched

Jun 10, 2026 - 18:49 vuln.today

Analysis Generated

Jun 10, 2026 - 18:49 vuln.today

CVE Published

Jun 10, 2026 - 17:34 nvd

HIGH 8.5

DescriptionNVD

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.

Articles & Coverage 1

News 12 New Kubernetes Vulnerabilities - 5 Critical, 7 High Severity Jun 11, 2026

AnalysisAI

Privilege escalation in Fission (Kubernetes-native serverless framework) prior to version 1.25.0 allows a tenant with permission to create Function or Environment CRDs to obtain CAP_SYS_TIME inside function/runtime containers by bypassing an incomplete capability denylist in the ValidatePodSpecSafety admission webhook. The denylist only blocked six Linux capabilities (SYS_ADMIN, NET_ADMIN, SYS_PTRACE, SYS_MODULE, DAC_READ_SEARCH, DAC_OVERRIDE) and omitted CAP_SYS_TIME and others, letting tenant-controlled code modify the container's system clock. No public exploit identified at time of analysis, but the upstream patch and CRD diff are publicly visible in fission/fission PR #3465.

Technical ContextAI

Fission is a serverless framework that runs tenant Functions and Environments as Kubernetes pods. The vulnerable code path is the admission control layer in pkg/apis/core/v1/podspec_safety.go (ValidatePodSpecSafety / ValidateContainerSafety) together with the executor-side sanitizeContainerSecurityContext merge layer, both of which gated securityContext.capabilities.add against a hard-coded denylist rather than an allowlist. This is a textbook CWE-269 (Improper Privilege Management) failure: a denylist of dangerous Linux capabilities will always be incomplete because the Linux capability set is large (40+ capabilities) and any omission becomes a direct privilege-add primitive. CAP_SYS_TIME specifically grants the ability to set the system clock and real-time clock via settimeofday/clock_settime, which on shared kernels affects time observed by other workloads on the node.

RemediationAI

Vendor-released patch: upgrade Fission to version 1.25.0 or later, which replaces the capability denylist with a strict allowlist limited to NET_BIND_SERVICE and adds CEL x-kubernetes-validations on the Function and Environment CRDs to enforce hostNetwork/hostPID/hostIPC=false, no serviceAccount override, no privileged or allowPrivilegeEscalation containers, and capability-add restricted to NET_BIND_SERVICE at the API-server admission stage (see https://github.com/fission/fission/pull/3465 and https://github.com/fission/fission/releases/tag/v1.25.0). If upgrading immediately is not possible, compensating controls include: restricting RBAC so only trusted operators can create or update fission.io Function and Environment CRDs (trade-off: breaks self-service tenant workflows); deploying a cluster-wide policy engine such as Kyverno or OPA Gatekeeper to reject Pods or Fission CRDs whose container securityContext.capabilities.add contains anything other than NET_BIND_SERVICE (trade-off: requires policy engine deployment and careful rule scoping); and enforcing the Pod Security Admission 'restricted' profile on the namespaces where Fission runtime/builder pods land, which natively forbids all added capabilities except NET_BIND_SERVICE (trade-off: may block other legitimate Fission features that rely on extra permissions).