EUVD-2026-36074Severity by source
AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L
Lifecycle Timeline
4DescriptionNVD
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
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. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Requires the attacker to already hold Kubernetes RBAC permission to create or update fission.io/v1 Function or Environment custom resources in a namespace served by a Fission installation prior to 1.25.0; this is the PR:L authenticated tenant role rather than a cluster-admin. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 8.5 with vector AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L reflects a low-privileged authenticated tenant (PR:L) being able to cross a trust boundary (Scope:Changed) into the container/node, with high integrity impact but no confidentiality impact and only low availability impact - consistent with clock manipulation rather than full RCE-as-root. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker with tenant-level Kubernetes access that permits creating fission.io Function or Environment CRDs submits a manifest whose podspec sets securityContext.capabilities.add: ["SYS_TIME"]. The Fission admission webhook's denylist check passes because SYS_TIME is not in its six-entry block list, the executor merges the securityContext without stripping it, and the resulting runtime pod runs attacker-controlled code with CAP_SYS_TIME - allowing the attacker to call clock_settime / settimeofday to shift the container's (and on shared kernels, the node's) system clock, breaking time-dependent security controls such as certificate validity, Kerberos/TOTP authentication, and audit log timestamps. |
| Remediation | 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). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Identify all Fission deployments and determine their current versions; prioritize environments with untrusted or semi-trusted tenants. …
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