{
    "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": "2026-09-16T10:12:00.087Z"
    },
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        "cna": {
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                "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": [
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                            "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"
                    ]
                }
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            "metrics": [
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                        "type": "Textual description of severity",
                        "content": {
                            "text": "important"
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                    "scenarios": [
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                            "lang": "en",
                            "value": "GENERAL"
                        }
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            "credits": [
                {
                    "lang": "en",
                    "value": "Youlong Chen Institute of Computing Technology <chenyoulong20g@ict.ac.cn>",
                    "type": "reporter"
                }
            ],
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            {
                "title": "CVE Program Container",
                "references": [
                    {
                        "url": "http://www.openwall.com/lists/oss-security/2026/09/15/6"
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                    "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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}