{"id":"CVE-2026-49822","title":"Fission: Cross-namespace event leakage via KubernetesWatchTrigger allows persistent tenant surveillance","summary":"Fission: Cross-namespace event leakage via KubernetesWatchTrigger allows persistent tenant surveillance","severity":"high","cvss":7.7,"cwe":["CWE-284","CWE-862"],"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-gc3j-79f2-7vvw","references":[{"url":"https://github.com/fission/fission/security/advisories/GHSA-gc3j-79f2-7vvw"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49822"},{"url":"https://github.com/fission/fission/pull/3379"},{"url":"https://github.com/fission/fission/commit/e2b92663499f4dc3a1e2d38178f39c3c65e0134a"},{"url":"https://github.com/fission/fission/releases/tag/v1.24.0"},{"url":"https://github.com/advisories/GHSA-gc3j-79f2-7vvw"}],"tags":["ghsa","go"],"epss":0.00231,"epssPercentile":0.14177,"ingestedAt":"2026-06-30T21:24:14.414Z","slug":"CVE-2026-49822","body":"## Overview\n\n### Summary\n\nA low-privilege developer who could create a `KubernetesWatchTrigger` (KWT) in their own namespace was able to establish a persistent surveillance channel over any other namespace.\n\n### Details\n\nTwo independent flaws compounded:\n\n1. `pkg/kubewatcher/kubewatcher.go::createKubernetesWatch` used `w.Spec.Namespace` (user-controlled) directly as the Watch target without checking it against `w.Namespace` (the KWT's own namespace). `kubewatcher` established the Watch\nusing its cluster-scoped service account and serialized every Pod/Service/Job change event as full JSON over HTTP POST to the attacker's function.\n2. The validating webhook (`pkg/webhook/kuberneteswatchtrigger.go`) registered `verbs=create` only, so `update`/`patch` requests bypassed validation entirely.\n\nA separate leak: an empty `spec.namespace` resolved to **all namespaces** via the controller's default, letting an attacker omit the field to surveil the entire cluster.\n\n### Impact\n\nA tenant with `kuberneteswatchtriggers.fission.io/create` could continuously receive full event payloads for Pods, Services, and Jobs in any namespace — a persistent cross-tenant surveillance channel requiring no additional privileges.\n\n### Fix\n\nFixed in [#3379](https://github.com/fission/fission/pull/3379) and released in [v1.24.0](https://github.com/fission/fission/releases/tag/v1.24.0).\n\n- The validating webhook marker is extended to `verbs=create;update`.\n- `Validate` rejects `KubernetesWatchTrigger.spec.namespace != metadata.namespace`.\n- A controller guard in `createKubernetesWatch` rejects cross-namespace targets that bypass admission and coerces an empty `Spec.Namespace` to the trigger's own namespace.\n\n### Behavioural change\n\nKubernetesWatchTriggers with an unset `spec.namespace` now watch only their own namespace instead of all namespaces. Anyone relying on the previous all-namespaces behaviour must create a separate KWT per namespace.\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":"twilight","depthScore":42,"depthScoreParts":{"impact":42.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}