{"id":"CVE-2026-122316","kind":"vulnerability","aliases":["CVE-2026-122316"],"related":[],"title":"Kyverno: namespaced tenants can modify resources outside their namespace","description":"Kyverno from 1.17.0 before 1.19.2 contains a missing authorization vulnerability in the mutate-existing background processor that allows namespaced tenants to modify resources outside their namespace. Attackers can create a NamespacedMutatingPolicy targeting Namespace objects or victim-namespace resources via CEL expressions, making the background-controller ServiceAccount strip Pod Security labels cluster-wide.","summary":"Kyverno's mutate-existing background processor lacks an authorization check, so a namespace tenant can create a NamespacedMutatingPolicy that changes objects in other namespaces. The attack makes the background-controller service account strip Pod Security labels cluster-wide.","severity":"high","cvss":8.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["kubernetes","kyverno","multi-tenant","runtime"],"not_affected_if":["kyverno-1.19.2-or-later","single-tenant-cluster"],"how_to_check":"- Check the installed Kyverno version with `kubectl get deploy -n kyverno -o jsonpath='{.items[*].spec.template.spec.containers[*].image}'`\n- List NamespacedMutatingPolicy objects with `kubectl get namespacedmutatingpolicies -A` and review which tenants can create them","fix":"- Kyverno: move to `1.19.2` or later (the sources state fixed versions from 1.17.0 before 1.19.2)","status":"open","published_at":"2026-11-05T03:17:24+00:00","first_seen_at":"2026-11-05T03:31:42+00:00","triaged_at":"2026-11-05T03:33:16+00:00","updated_at":"2026-11-05T03:33:16+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-05T03:33:16Z","model":"claude-haiku-5-5","output":{"fix":"- Kyverno: move to `1.19.2` or later (the sources state fixed versions from 1.17.0 before 1.19.2)","reach":"network","title":"Kyverno: namespaced tenants can modify resources outside their namespace","impact":"high","summary":"Kyverno's mutate-existing background processor lacks an authorization check, so a namespace tenant can create a NamespacedMutatingPolicy that changes objects in other namespaces. The attack makes the background-controller service account strip Pod Security labels cluster-wide.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["kubernetes","kyverno","multi-tenant"],"confidence":0.6,"fix_status":"available","needs_auth":"yes","worst_case":"tenant strips Pod Security labels cluster-wide, weakening isolation","analyst_note":"Confirm the affected version range and whether the vendor advisory on github.com names extra prerequisites for the NamespacedMutatingPolicy path.","how_to_check":"- Check the installed Kyverno version with `kubectl get deploy -n kyverno -o jsonpath='{.items[*].spec.template.spec.containers[*].image}'`\n- List NamespacedMutatingPolicy objects with `kubectl get namespacedmutatingpolicies -A` and review which tenants can create them\n- unknown for further checks","plain_action":"","needs_analyst":true,"not_affected_if":["single-tenant-cluster","kyverno-1.19.2-or-later"],"who_is_affected":"Clusters running Kyverno from 1.17.0 up to but not including 1.19.2 where namespace tenants can create NamespacedMutatingPolicy resources. The flaw lets a tenant reach objects outside their own namespace and strip Pod Security labels cluster-wide. Clusters with no multi-tenant namespace access or a patched Kyverno can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000779,"input_tokens":4312,"output_tokens":695,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-122316':12A,15A '-2026':11A,14A '1.17.0':65C '1.19.2':67C 'account':55B 'allow':81C 'attack':48B,90C 'author':31B,71C 'background':27B,52B,78C,109C 'background-control':51B,108C 'cel':104C 'chang':42B 'check':32B 'cluster':61B,117C 'cluster-wid':60B,116C 'contain':68C 'control':53B,110C 'creat':38B,92C 'cve':10A,13A 'exist':26B,77C 'express':105C 'kubernet':16B 'kyverno':1A,17B,22B,63C 'label':59B,115C 'lack':29B 'make':49B,106C 'miss':70C 'modifi':5A,85C 'multi':19B 'multi-ten':18B 'mutat':25B,76C 'mutate-exist':24B,75C 'namespac':2A,9A,35B,46B,82C,89C,96C,101C 'namespacedmutatingpolici':40B,94C 'object':43B,97C 'outsid':7A,87C 'pod':57B,113C 'processor':28B,79C 'resourc':6A,86C,102C 'runtim':21B 'secur':58B,114C 'servic':54B 'serviceaccount':111C 'strip':56B,112C 'target':95C 'tenant':3A,20B,36B,83C 'via':103C 'victim':100C 'victim-namespac':99C 'vulner':72C 'wide':62B,118C","nicknames":[],"mitigations":[],"who_affected":"Clusters running Kyverno from 1.17.0 up to but not including 1.19.2 where namespace tenants can create NamespacedMutatingPolicy resources. The flaw lets a tenant reach objects outside their own namespace and strip Pod Security labels cluster-wide. Clusters with no multi-tenant namespace access or a patched Kyverno can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","kubernetes","kyverno","multitenant","runtime"],"campaign_type":null,"first_public_at":"2026-10-21T15:55:06+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-122316","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-122316","severity":null,"published_at":"2026-11-05T03:17:24+00:00","modified_at":"2026-11-05T03:17:24+00:00","first_seen_at":"2026-11-05T03:31:42+00:00","fetched_at":"2026-11-05T03:31:42+00:00","note":null}],"documents":[{"id":72714,"url":"https://github.com/kyverno/kyverno/security/advisories/GHSA-vm98-8c25-h274","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-21T15:55:06+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":72715,"url":"https://www.vulncheck.com/advisories/kyverno-1.17.0-before-1.19.2-cross-namespace-write-via-namespacedmutatingpolicy-mutateexisting","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"exploit_sources":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}