{"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\u00a0key=value\u00a0format, the injected tabs are parsed as legitimate field separators, allowing the attacker to spoof audit results (e.g., injecting\u00a0result=success), forge operation types, and corrupt forensic evidence.\n\nA log injection vulnerability in Apache ZooKeeper allows a client that can call\u00a0setACL\u00a0to inject forged key-value fields into\u00a0zookeeper_audit.log. When audit logging is enabled, the server serializes attacker-controlled digest ACL ids into the\u00a0acl=\u00a0audit field without escaping tab characters. Because audit events are emitted as tab-separated\u00a0key=value\u00a0records, a crafted ACL id can make one successful\u00a0setAcl\u00a0event appear to contain forged fields such as\u00a0operation=delete\u00a0and\u00a0znode=/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>. 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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.", "supportingMedia": [{"type": "text/html", "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. 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