{"id":"CVE-2026-122309","kind":"vulnerability","aliases":["CVE-2026-122309"],"related":[],"title":"Kyverno: namespace policy authors can crash admission controller with CEL expressions","description":"Kyverno before 1.19.2 contains a denial of service vulnerability that allows namespace-scoped policy authors to exhaust CPU and memory by submitting CEL expressions evaluated without runtime cost limits. Attackers can create a NamespacedValidatingPolicy or NamespacedDeletingPolicy with nested map comprehensions over large ConfigMap fields to OOM-kill Kyverno pods and block cluster-wide admission.","summary":"Kyverno before 1.19.2 evaluates CEL expressions in namespace-scoped policies without runtime cost limits. A namespace policy author can use nested map comprehensions over large ConfigMaps to exhaust CPU and memory, get Kyverno pods OOM-killed, and block cluster-wide admission.","severity":"high","cvss":8.2,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","kubernetes","kyverno","self-hosted"],"not_affected_if":["kyverno-1.19.2-or-later","no-namespaced-policy-authors"],"how_to_check":"- Check the Kyverno version with `kubectl get deploy -n kyverno kyverno-admission-controller -o jsonpath='{.spec.template.spec.containers[0].image}'`\n- Check whether users outside platform teams can create `NamespacedValidatingPolicy` or `NamespacedDeletingPolicy` resources","fix":"- Kyverno: move to `1.19.2` or later","status":"open","published_at":"2026-11-05T03:17:23+00:00","first_seen_at":"2026-11-05T03:31:41+00:00","triaged_at":"2026-11-05T03:33:23+00:00","updated_at":"2026-11-05T03:33:23+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-11-05T03:33:23Z","model":"claude-haiku-5-5","output":{"fix":"- Kyverno: move to `1.19.2` or later","reach":"network","title":"Kyverno: namespace policy authors can crash admission controller with CEL expressions","impact":"medium","summary":"Kyverno before 1.19.2 evaluates CEL expressions in namespace-scoped policies without runtime cost limits. A namespace policy author can use nested map comprehensions over large ConfigMaps to exhaust CPU and memory, get Kyverno pods OOM-killed, and block cluster-wide admission.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["kubernetes","kyverno","self-hosted"],"confidence":0.6,"fix_status":"available","needs_auth":"yes","worst_case":"Kyverno pods are OOM-killed and cluster-wide admission stops","analyst_note":"","how_to_check":"- Check the Kyverno version with `kubectl get deploy -n kyverno kyverno-admission-controller -o jsonpath='{.spec.template.spec.containers[0].image}'`\n- Check whether users outside platform teams can create `NamespacedValidatingPolicy` or `NamespacedDeletingPolicy` resources","plain_action":"","needs_analyst":false,"not_affected_if":["kyverno-1.19.2-or-later","no-namespaced-policy-authors"],"who_is_affected":"Clusters running Kyverno before 1.19.2 where teams other than platform admins can create namespaced Kyverno policies. A namespace policy author can exhaust Kyverno's resources and block admission across the cluster. Clusters where only cluster administrators write policies are less exposed.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000737,"input_tokens":4318,"output_tokens":611,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-122309':14A,17A '-2026':13A,16A '1.19.2':26B,70C 'admiss':7A,67B,124C 'allow':78C 'attack':98C 'author':4A,42B,83C 'block':63B,120C 'cel':10A,28B,91C 'cluster':65B,122C 'cluster-wid':64B,121C 'comprehens':47B,108C 'configmap':50B,111C 'contain':71C 'control':8A 'cost':37B,96C 'cpu':53B,86C 'crash':6A 'creat':100C 'cve':12A,15A 'denial':73C 'evalu':27B,93C 'exhaust':52B,85C 'express':11A,29B,92C 'field':112C 'get':56B 'host':23B 'infrastructur':18B 'kill':61B,116C 'kubernet':19B 'kyverno':1A,20B,24B,57B,68C,117C 'larg':49B,110C 'limit':38B,97C 'map':46B,107C 'memori':55B,88C 'namespac':2A,32B,40B,80C 'namespace-scop':31B,79C 'namespaceddeletingpolici':104C 'namespacedvalidatingpolici':102C 'nest':45B,106C 'oom':60B,115C 'oom-kil':59B,114C 'pod':58B,118C 'polici':3A,34B,41B,82C 'runtim':36B,95C 'scope':33B,81C 'self':22B 'self-host':21B 'servic':75C 'submit':90C 'use':44B 'vulner':76C 'wide':66B,123C 'without':35B,94C","nicknames":[],"mitigations":[],"who_affected":"Clusters running Kyverno before 1.19.2 where teams other than platform admins can create namespaced Kyverno policies. A namespace policy author can exhaust Kyverno's resources and block admission across the cluster. Clusters where only cluster administrators write policies are less exposed.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","infrastructure","kubernetes","kyverno","selfhosted"],"campaign_type":null,"first_public_at":"2026-10-21T15:44:17+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/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-2026-122309","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-122309","severity":null,"published_at":"2026-11-05T03:17:23+00:00","modified_at":"2026-11-05T03:17:23+00:00","first_seen_at":"2026-11-05T03:31:41+00:00","fetched_at":"2026-11-05T03:31:41+00:00","note":null}],"documents":[{"id":72696,"url":"https://github.com/kyverno/kyverno/security/advisories/GHSA-m8p2-qqmx-j53x","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-21T15:44:17+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":72697,"url":"https://www.vulncheck.com/advisories/kyverno-before-1.19.2-denial-of-service-via-unbounded-cel-policy-evaluation-cost","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"}