{"id":"CVE-2026-118952","kind":"vulnerability","aliases":["CVE-2026-118952"],"related":[],"title":"Kroxylicious: ACL prefix matching can let a Kafka client read denied topics","description":"A flaw was found in the Kroxylicious ACL authorizer. Its prefix-matching logic may apply a rule to a principal of a different type, or fail to check a broader matching rule when prefixes overlap. Depending on the ACL configuration, this may allow an authenticated Kafka client to access a resource (such as read a topic) that should be denied.","summary":"Kroxylicious, a Kafka proxy, has a flaw in its ACL authorizer where overlapping prefix rules may be applied to the wrong principal or skipped. An authenticated Kafka client may therefore access a resource such as a topic that the ACL configuration should deny.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["acl","infrastructure","kafka","kroxylicious"],"not_affected_if":["no-kafka-authenticated-clients","no-kroxylicious","no-prefix-acl-rules"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-10-30T07:16:33+00:00","first_seen_at":"2026-10-30T07:29:00+00:00","triaged_at":"2026-10-30T07:30:08+00:00","updated_at":"2026-10-30T07:30:08+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-30T07:30:08Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Kroxylicious: ACL prefix matching can let a Kafka client read denied topics","impact":"medium","summary":"Kroxylicious, a Kafka proxy, has a flaw in its ACL authorizer where overlapping prefix rules may be applied to the wrong principal or skipped. An authenticated Kafka client may therefore access a resource such as a topic that the ACL configuration should deny.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["kroxylicious","kafka","acl"],"confidence":0.6,"fix_status":"unknown","needs_auth":"yes","worst_case":"authenticated Kafka client reads topics it should be denied","analyst_note":"Find affected and fixed Kroxylicious versions and the ACL configuration that triggers the flaw, via the NVD entry or the project's advisory.","how_to_check":"- unknown","plain_action":"","needs_analyst":true,"not_affected_if":["no-kroxylicious","no-prefix-acl-rules","no-kafka-authenticated-clients"],"who_is_affected":"Only deployments that run the Kroxylicious proxy with its ACL authorizer and prefix-based rules are exposed, and the attacker must already hold valid Kafka credentials. Teams not using Kroxylicious ACLs can skip it. The sources do not name affected versions.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000673,"input_tokens":4124,"output_tokens":521,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-118952':15A,18A '-2026':14A,17A 'access':53B,115C 'acl':2A,19B,32B,62B,73C,105C 'allow':109C 'appli':40B,81C 'authent':48B,111C 'author':33B,74C 'broader':96C 'check':94C 'client':9A,50B,113C 'configur':63B,106C 'cve':13A,16A 'deni':11A,65B,126C 'depend':102C 'differ':89C 'fail':92C 'flaw':29B,67C 'found':69C 'infrastructur':20B 'kafka':8A,21B,25B,49B,112C 'kroxylici':1A,22B,23B,72C 'let':6A 'logic':79C 'match':4A,78C,97C 'may':38B,51B,80C,108C 'overlap':35B,101C 'prefix':3A,36B,77C,100C 'prefix-match':76C 'princip':44B,86C 'proxi':26B 'read':10A,120C 'resourc':55B,117C 'rule':37B,83C,98C 'skip':46B 'therefor':52B 'topic':12A,59B,122C 'type':90C 'wrong':43B","nicknames":[],"mitigations":[],"who_affected":"Only deployments that run the Kroxylicious proxy with its ACL authorizer and prefix-based rules are exposed, and the attacker must already hold valid Kafka credentials. Teams not using Kroxylicious ACLs can skip it. The sources do not name affected versions.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"first_public_at":"2026-10-30T07:16:33+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","cvss_by":"secalert@redhat.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-118952","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118952","severity":null,"published_at":"2026-10-30T07:16:33+00:00","modified_at":"2026-10-30T07:16:33+00:00","first_seen_at":"2026-10-30T07:29:00+00:00","fetched_at":"2026-10-30T07:29:00+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}