{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-84439","assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","state":"PUBLISHED","assignerShortName":"apache","dateReserved":"2026-09-01T19:22:00.838Z","datePublished":"2026-09-16T09:27:46.439Z","dateUpdated":"2026-09-17T19:14:53.953Z"},"containers":{"cna":{"providerMetadata":{"orgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","shortName":"apache","dateUpdated":"2026-09-16T09:27:46.439Z"},"title":"Apache ZooKeeper: Audit log injection via unsanitized output from multiple sources","problemTypes":[{"descriptions":[{"description":"CWE-117 Improper output neutralization for logs","lang":"en","cweId":"CWE-117","type":"CWE"}]}],"source":{"discovery":"UNKNOWN"},"affected":[{"vendor":"Apache Software Foundation","product":"Apache ZooKeeper","collectionURL":"https://repo.maven.apache.org/maven2","packageName":"org.apache.zookeeper:zookeeper","packageURL":"pkg:maven/org.apache.zookeeper/zookeeper","versions":[{"status":"affected","version":"3.9.0","lessThanOrEqual":"3.9.5","versionType":"maven"},{"status":"affected","version":"3.8.0","lessThanOrEqual":"3.8.6","versionType":"maven"}],"defaultStatus":"unaffected"}],"descriptions":[{"value":"When audit logging is enabled (zookeeper.audit.enable=true), an unauthenticated attacker can inject arbitrary fields into Apache ZooKeeper's audit log by sending a digest authentication request with tab characters (\\t) embedded in the username. Because the audit log uses tab-separated key=value format, the injected tabs are parsed as legitimate field separators, allowing the attacker to spoof audit results (e.g., injecting result=success), forge operation types, and corrupt forensic evidence.\n\nA log injection vulnerability in Apache ZooKeeper allows a client that can call setACL to inject forged key-value fields into zookeeper_audit.log. When audit logging is enabled, the server serializes attacker-controlled digest ACL ids into the acl= audit field without escaping tab characters. Because audit events are emitted as tab-separated key=value records, a crafted ACL id can make one successful setAcl event appear to contain forged fields such as operation=delete and znode=/forged. This undermines the integrity of downstream audit parsing, alerting, and incident response.\n\nThis issue affects Apache ZooKeeper: from 3.9.0 through 3.9.5, from 3.8.0 through 3.8.6.\n\nUsers are recommended to upgrade to version 3.9.6 or 3.8.7, which fixes the issue.","lang":"en","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>When audit logging is enabled (<code>zookeeper.audit.enable=true</code>), an unauthenticated attacker can inject arbitrary fields into Apache ZooKeeper's audit log by sending a digest authentication request with tab characters (<code>\\t</code>) embedded in the username. Because the audit log uses tab-separated&nbsp;<code>key=value</code>&nbsp;format, the injected tabs are parsed as legitimate field separators, allowing the attacker to spoof audit results (e.g., injecting&nbsp;<code>result=success</code>), forge operation types, and corrupt forensic evidence.<br><span><br>A log injection vulnerability in Apache ZooKeeper allows a client that can call&nbsp;</span><code>setACL</code><span>&nbsp;</span><span>to inject forged key-value fields into</span><span>&nbsp;</span><code>zookeeper_audit.log</code><span>. When audit logging is enabled, the server serializes attacker-controlled digest ACL ids into the</span><span>&nbsp;</span><code>acl=</code><span>&nbsp;</span><span>audit field without escaping tab characters. Because audit events are emitted as tab-separated</span><span>&nbsp;</span><code>key=value</code><span>&nbsp;</span><span>records, a crafted ACL id can make one successful</span><span>&nbsp;</span><code>setAcl</code><span>&nbsp;</span><span>event appear to contain forged fields such as</span><span>&nbsp;</span><code>operation=delete</code><span>&nbsp;</span><span>and</span><span>&nbsp;</span><code>znode=/forged</code><span>. This undermines the integrity of downstream audit parsing, alerting, and incident response.</span><span><br></span><span><br>This issue affects Apache ZooKeeper: from 3.9.0 through 3.9.5, from 3.8.0 through 3.8.6.<br></span><span><br>Users are recommended to upgrade to version 3.9.6 or 3.8.7, which fixes the issue.</span></p>"}]}],"references":[{"url":"https://lists.apache.org/thread/b7qnjvqjh393l0j07tmnb5ggg40sx3m6","tags":["vendor-advisory"]}],"metrics":[{"other":{"type":"Textual description of severity","content":{"text":"important"}},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"credits":[{"lang":"en","value":"Youlong Chen Institute of Computing Technology <chenyoulong20g@ict.ac.cn>","type":"reporter"}],"x_generator":{"engine":"Vulnogram 1.0.3"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/09/15/6"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2026-09-16T10:12:00.087Z"}},{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.3,"attackVector":"NETWORK","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","integrityImpact":"LOW","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-09-17T19:14:36.442526Z","id":"CVE-2026-84439","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-17T19:14:53.953Z"}}]}}