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        "providerMetadata": {
          "dateUpdated": "2026-09-16T10:12:00.087Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/09/15/6"
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        ],
        "title": "CVE Program Container"
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    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.maven.apache.org/maven2",
          "defaultStatus": "unaffected",
          "packageName": "org.apache.zookeeper:zookeeper",
          "packageURL": "pkg:maven/org.apache.zookeeper/zookeeper",
          "product": "Apache ZooKeeper",
          "vendor": "Apache Software Foundation",
          "versions": [
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              "lessThanOrEqual": "3.9.5",
              "status": "affected",
              "version": "3.9.0",
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              "version": "3.8.0",
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      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Youlong Chen Institute of Computing Technology \u003cchenyoulong20g@ict.ac.cn\u003e"
        }
      ],
      "descriptions": [
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              "value": "\u003cp\u003eWhen audit logging is enabled (\u003ccode\u003ezookeeper.audit.enable=true\u003c/code\u003e), an unauthenticated attacker can inject arbitrary fields into Apache ZooKeeper\u0027s audit log by sending a digest authentication request with tab characters (\u003ccode\u003e\\t\u003c/code\u003e) embedded in the username. Because the audit log uses tab-separated\u0026nbsp;\u003ccode\u003ekey=value\u003c/code\u003e\u0026nbsp;format, the injected tabs are parsed as legitimate field separators, allowing the attacker to spoof audit results (e.g., injecting\u0026nbsp;\u003ccode\u003eresult=success\u003c/code\u003e), forge operation types, and corrupt forensic evidence.\u003cbr\u003e\u003cspan\u003e\u003cbr\u003eA log injection vulnerability in Apache ZooKeeper allows a client that can call\u0026nbsp;\u003c/span\u003e\u003ccode\u003esetACL\u003c/code\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003cspan\u003eto inject forged key-value fields into\u003c/span\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003ccode\u003ezookeeper_audit.log\u003c/code\u003e\u003cspan\u003e. When audit logging is enabled, the server serializes attacker-controlled digest ACL ids into the\u003c/span\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003ccode\u003eacl=\u003c/code\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003cspan\u003eaudit field without escaping tab characters. Because audit events are emitted as tab-separated\u003c/span\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003ccode\u003ekey=value\u003c/code\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003cspan\u003erecords, a crafted ACL id can make one successful\u003c/span\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003ccode\u003esetAcl\u003c/code\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003cspan\u003eevent appear to contain forged fields such as\u003c/span\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003ccode\u003eoperation=delete\u003c/code\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003cspan\u003eand\u003c/span\u003e\u003cspan\u003e\u0026nbsp;\u003c/span\u003e\u003ccode\u003eznode=/forged\u003c/code\u003e\u003cspan\u003e. This undermines the integrity of downstream audit parsing, alerting, and incident response.\u003c/span\u003e\u003cspan\u003e\u003cbr\u003e\u003c/span\u003e\u003cspan\u003e\u003cbr\u003eThis issue affects Apache ZooKeeper: from 3.9.0 through 3.9.5, from 3.8.0 through 3.8.6.\u003cbr\u003e\u003c/span\u003e\u003cspan\u003e\u003cbr\u003eUsers are recommended to upgrade to version 3.9.6 or 3.8.7, which fixes the issue.\u003c/span\u003e\u003c/p\u003e"
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          "value": "When audit logging is enabled (zookeeper.audit.enable=true), an unauthenticated attacker can inject arbitrary fields into Apache ZooKeeper\u0027s 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."
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              "text": "important"
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            "type": "Textual description of severity"
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          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
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      "problemTypes": [
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          "descriptions": [
            {
              "cweId": "CWE-117",
              "description": "CWE-117 Improper output neutralization for logs",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T09:27:46.439Z",
        "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
        "shortName": "apache"
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      "references": [
        {
          "tags": [
            "vendor-advisory"
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          "url": "https://lists.apache.org/thread/b7qnjvqjh393l0j07tmnb5ggg40sx3m6"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Apache ZooKeeper: Audit log injection via unsanitized output from multiple sources",
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  "cveMetadata": {
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    "assignerShortName": "apache",
    "cveId": "CVE-2026-84439",
    "datePublished": "2026-09-16T09:27:46.439Z",
    "dateReserved": "2026-09-01T19:22:00.838Z",
    "dateUpdated": "2026-09-16T10:12:00.087Z",
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