{"id":"CVE-2026-50563","title":"Fission Container Executor Function PodSpec Injection Leading to Node Escape","summary":"Fission Container Executor Function PodSpec Injection Leading to Node Escape","severity":"critical","cvss":9.9,"cwe":["CWE-269","CWE-284"],"vendor":"fission","product":"github.com/fission/fission","ecosystem":"go","affected":["github.com/fission/fission <= 1.23.0"],"patched":["github.com/fission/fission 1.24.0"],"published":"2026-06-30","updated":"2026-06-30","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-v455-mv2v-5g92","references":[{"url":"https://github.com/fission/fission/security/advisories/GHSA-v455-mv2v-5g92"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50563"},{"url":"https://github.com/fission/fission/pull/3391"},{"url":"https://github.com/fission/fission/commit/e484df8460bb4e8026e24210120602aa7f181f64"},{"url":"https://github.com/fission/fission/releases/tag/v1.24.0"},{"url":"https://github.com/advisories/GHSA-v455-mv2v-5g92"}],"tags":["ghsa","go"],"epss":0.00274,"epssPercentile":0.20039,"ingestedAt":"2026-06-30T21:24:14.408Z","slug":"CVE-2026-50563","body":"## Overview\n\n### Summary\n\nFission's Container Executor path lets a tenant supply `Function.spec.podspec` directly; the executor merges it into the executor-built podspec and creates a Deployment whose pods run the user's container image.\n\n### Details\n\nTwo flaws compounded:\n\n1. `pkg/apis/core/v1/validation.go::FunctionSpec.Validate` only checked that `spec.PodSpec != nil` when `executorType: container`; it did not inspect the content of `spec.PodSpec`.\n2. `pkg/executor/util/merge.go::MergePodSpec` unconditionally forwarded `hostPID`, `hostNetwork`, `hostIPC`, hostPath volumes, `serviceAccountName`, and container `privileged` into the Deployment spec via the container-executor sink\n(`pkg/executor/executortype/container/deployment.go::getDeploymentSpec`).\n\nA tenant with only `functions.fission.io/create` could deploy a Function with a crafted podspec that mounted the host root filesystem and shared host namespaces. The executor — running under its high-privilege SA, which holds\n`deployments/create` on the function namespace — created that Deployment on the tenant's behalf, turning Function-create into effective `deployments/create` with arbitrary pod-security configuration.\n\nThis is the Function-CRD sibling of GHSA-gx55-f84r-v3r7 / GHSA-wmgg-3p4h-48x7, with a **lower** attack threshold: regular function developers typically hold `functions/create` but not `environments/create`.\n\n### Impact\n\nA tenant with only `functions.fission.io/create` is escalated to node escape via a privileged, host-namespace pod scheduled by the executor.\n\n### Fix\n\nFixed in [#3391](https://github.com/fission/fission/pull/3391) and released in [v1.24.0](https://github.com/fission/fission/releases/tag/v1.24.0).\n\n- `FunctionSpec.Validate` now calls `ValidatePodSpecSafety(\"Function.spec.podspec\", spec.PodSpec)` after the existing `spec.PodSpec == nil` check.\n- The Function validating webhook is already registered on `verbs=create;update`, so it picks up the new validation with no marker change.\n- The same merge-layer strip and per-container sanitize used for the Environment path applies here, since the container-executor sink calls `util.MergePodSpec`.\n\nSee GHSA-gx55-f84r-v3r7 for the detailed fix.\n\n### Behavioural change\n\nFunctions whose `spec.podspec` sets host namespaces, hostPath volumes, container `privileged`/`allowPrivilegeEscalation`, dangerous Linux capabilities, or a `serviceAccountName` override are now rejected at admission. Legitimate\ncontainer-executor functions that set `image`, `command`, `args`, `env`, `resources`, `nodeSelector`, `tolerations`, `affinity`, non-hostPath `volumes`, or `volumeMounts` are unaffected.\n\n## Affected packages\n\n- `github.com/fission/fission <= 1.23.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `github.com/fission/fission 1.24.0`","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":54.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}