{"id":"CVE-2026-122306","kind":"vulnerability","aliases":["CVE-2026-122306"],"related":[],"title":"Kyverno: crafted policy wildcards let namespace users exhaust admission controller CPU","description":"Kyverno before 1.19.2 contains a denial of service vulnerability that allows namespaced policy authors to exhaust admission controller CPU by submitting pathological wildcard patterns. Attackers can create a Policy with crafted match and exclude names evaluated by ValidateMatchExcludeConflict, pinning cores and causing cluster-wide webhook timeouts that block resource operations.","summary":"Kyverno versions before 1.19.2 evaluate crafted wildcard patterns in policy match and exclude names in a way that pins CPU on the admission controller. A user who can create a namespaced Policy can cause cluster-wide webhook timeouts that block resource operations.","severity":"high","cvss":8.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","kubernetes","kyverno","self-hosted"],"not_affected_if":["no-namespaced-policy-authors","version-1.19.2-or-later"],"how_to_check":"- Check the installed Kyverno version with `kubectl get deployment -n kyverno kyverno-admission-controller -o jsonpath='{.spec.template.spec.containers[0].image}'` (the version is in the image tag)\n- Review which users can create Policy objects in namespaces with `kubectl auth can-i create policies -n <namespace>`","fix":"- Kyverno: `1.19.2` or later (the sources state the fix is in versions before 1.19.2)","status":"open","published_at":"2026-11-05T03:17:22+00:00","first_seen_at":"2026-11-05T03:31:41+00:00","triaged_at":"2026-11-05T03:33:20+00:00","updated_at":"2026-11-05T03:33:20+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-11-05T03:33:20Z","model":"claude-haiku-5-5","output":{"fix":"- Kyverno: `1.19.2` or later (the sources state the fix is in versions before 1.19.2)","reach":"network","title":"Kyverno: crafted policy wildcards let namespace users exhaust admission controller CPU","impact":"medium","summary":"Kyverno versions before 1.19.2 evaluate crafted wildcard patterns in policy match and exclude names in a way that pins CPU on the admission controller. A user who can create a namespaced Policy can cause cluster-wide webhook timeouts that block resource operations.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["kubernetes","kyverno","self-hosted"],"confidence":0.6,"fix_status":"available","needs_auth":"yes","worst_case":"cluster-wide admission webhook timeouts block resource operations","analyst_note":"Confirm the exact affected version range and whether a workaround exists before 1.19.2; check the vendor advisory on github.com linked in the sources.","how_to_check":"- Check the installed Kyverno version with `kubectl get deployment -n kyverno kyverno-admission-controller -o jsonpath='{.spec.template.spec.containers[0].image}'` (the version is in the image tag)\n- Review which users can create Policy objects in namespaces with `kubectl auth can-i create policies -n <namespace>`","plain_action":"","needs_analyst":true,"not_affected_if":["version-1.19.2-or-later","no-namespaced-policy-authors"],"who_is_affected":"Clusters running Kyverno before 1.19.2 where users other than cluster administrators can create namespaced Policy objects. The admission controller's CPU is the target, so clusters that restrict Policy creation to trusted operators have less exposure. Clusters on 1.19.2 or later are not affected.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000762,"input_tokens":4299,"output_tokens":665,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-122306':14A,17A '-2026':13A,16A '1.19.2':27B,69C 'admiss':9A,46B,83C 'allow':77C 'attack':91C 'author':80C 'block':64B,115C 'caus':57B,108C 'cluster':59B,110C 'cluster-wid':58B,109C 'contain':70C 'control':10A,47B,84C 'core':106C 'cpu':11A,43B,85C 'craft':2A,29B,97C 'creat':52B,93C 'cve':12A,15A 'denial':72C 'evalu':28B,102C 'exclud':36B,100C 'exhaust':8A,82C 'host':23B 'infrastructur':18B 'kubernet':19B 'kyverno':1A,20B,24B,67C 'let':5A 'match':34B,98C 'name':37B,101C 'namespac':6A,54B,78C 'oper':66B,117C 'patholog':88C 'pattern':31B,90C 'pin':42B,105C 'polici':3A,33B,55B,79C,95C 'resourc':65B,116C 'self':22B 'self-host':21B 'servic':74C 'submit':87C 'timeout':62B,113C 'user':7A,49B 'validatematchexcludeconflict':104C 'version':25B 'vulner':75C 'way':40B 'webhook':61B,112C 'wide':60B,111C 'wildcard':4A,30B,89C","nicknames":[],"mitigations":[],"who_affected":"Clusters running Kyverno before 1.19.2 where users other than cluster administrators can create namespaced Policy objects. The admission controller's CPU is the target, so clusters that restrict Policy creation to trusted operators have less exposure. Clusters on 1.19.2 or later are not affected.","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":"2026-10-21T15:42:32+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/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-2026-122306","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-122306","severity":null,"published_at":"2026-11-05T03:17:22+00:00","modified_at":"2026-11-05T03:17:22+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":72690,"url":"https://github.com/kyverno/kyverno/security/advisories/GHSA-8mrj-27wr-599g","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-21T15:42:32+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":72691,"url":"https://www.vulncheck.com/advisories/kyverno-before-1.19.2-denial-of-service-via-exponential-time-wildcard-matching","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"}