{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-82431","assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","state":"PUBLISHED","assignerShortName":"apache","dateReserved":"2026-08-29T10:21:15.109Z","datePublished":"2026-09-14T14:14:48.439Z","dateUpdated":"2026-09-14T20:01:54.073Z"},"containers":{"cna":{"providerMetadata":{"orgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","shortName":"apache","dateUpdated":"2026-09-14T14:14:48.439Z"},"title":"Apache Storm Client: Authorization Bypass When nimbus.groups Is Configured Without nimbus.users","problemTypes":[{"descriptions":[{"description":"CWE-863 Incorrect Authorization","lang":"en","cweId":"CWE-863","type":"CWE"}]}],"source":{"discovery":"UNKNOWN"},"affected":[{"vendor":"Apache Software Foundation","product":"Apache Storm Client","collectionURL":"https://repo.maven.apache.org/maven2","packageName":"org.apache.storm:storm-client","versions":[{"status":"affected","version":"3.0.0","lessThan":"3.1.0","versionType":"semver"}],"defaultStatus":"unaffected"}],"descriptions":[{"value":"Description\n\n`SimpleACLAuthorizer` evaluated the user-level command set by returning early when `nimbus.users` was empty,\nbefore `nimbus.groups` was considered. An operator who restricted cluster access by group alone, leaving\n`nimbus.users` unset, therefore received no restriction at all: every authenticated principal was permitted\nevery user-level operation, including `submitTopology`, `beginFileUpload` and `getNimbusConf`.\n\n`docs/SECURITY.md` presents `nimbus.groups` as a supported way to lock down a cluster, so a deployment\nfollowing the documentation could believe it was restricted while it was not. The failure is silent; nothing\nin the logs or the configuration indicates that the group list is being ignored.\n\nBoth lists left empty continues to mean that no restriction is configured, which is the shipped default and\nis unchanged.\n\nMitigation\n\nUpgrade to 3.1.0, where `nimbus.groups` is evaluated whether or not `nimbus.users` is set.\n\nUsers who cannot upgrade immediately should additionally populate `nimbus.users` with the intended\nprincipals, since a non-empty user list causes the group list to be evaluated on affected versions.\nOperators should review Nimbus access logs for operations by principals outside the intended groups.\n\nNote that after upgrading, a cluster configured with `nimbus.groups` alone becomes restrictive for the first\ntime. This includes `NimbusClient`, which calls `getLeader` on every connection, so clients outside the\nconfigured groups will begin to be refused.\n\nCredit\n\nThe ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.","lang":"en","supportingMedia":[{"type":"text/html","base64":false,"value":"<b>Description</b><br><br>`SimpleACLAuthorizer` evaluated the user-level command set by returning early when `nimbus.users` was empty,<br>before `nimbus.groups` was considered. An operator who restricted cluster access by group alone, leaving<br>`nimbus.users` unset, therefore received no restriction at all: every authenticated principal was permitted<br>every user-level operation, including `submitTopology`, `beginFileUpload` and `getNimbusConf`.<br><br>`docs/SECURITY.md` presents `nimbus.groups` as a supported way to lock down a cluster, so a deployment<br>following the documentation could believe it was restricted while it was not. The failure is silent; nothing<br>in the logs or the configuration indicates that the group list is being ignored.<br><br>Both lists left empty continues to mean that no restriction is configured, which is the shipped default and<br>is unchanged.<br><br><b>Mitigation</b><br><br>Upgrade to 3.1.0, where `nimbus.groups` is evaluated whether or not `nimbus.users` is set.<br><br>Users who cannot upgrade immediately should additionally populate `nimbus.users` with the intended<br>principals, since a non-empty user list causes the group list to be evaluated on affected versions.<br>Operators should review Nimbus access logs for operations by principals outside the intended groups.<br><br>Note that after upgrading, a cluster configured with `nimbus.groups` alone becomes restrictive for the first<br>time. This includes `NimbusClient`, which calls `getLeader` on every connection, so clients outside the<br>configured groups will begin to be refused.<br><br><b>Credit</b><br><br>The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.<br>"}]}],"references":[{"url":"https://lists.apache.org/thread/s335qxb6woqb35ho3fpq7toytsz1gpts","tags":["vendor-advisory"]}],"metrics":[{"other":{"type":"Textual description of severity","content":{"text":"important"}},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"credits":[{"lang":"en","value":"The ASF using Claude Agents","type":"finder"}],"x_generator":{"engine":"Vulnogram 1.0.3"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/09/13/11"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2026-09-14T15:13:50.464Z"}},{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":9.8,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-09-14T20:01:33.385522Z","id":"CVE-2026-82431","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-14T20:01:54.073Z"}}]}}