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CVE-2026-84439Not scoredCWE-117

Apache ZooKeeper: Audit log injection via unsanitized output from multiple sources

Apache Software Foundation · Apache ZooKeeper

Not in CISA KEVVendor fix available
0.7%probability of exploitation in the next 30 days
54th percentile
050100

Higher than 54% of scored CVEs

Not scored yet. NVD has not published a CVSS score.

DescriptionNVD

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. A 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. This issue affects Apache ZooKeeper: from 3.9.0 through 3.9.5, from 3.8.0 through 3.8.6. Users are recommended to

Coverage1 article · 1 outlet

First in our coverage: SecurityOnline, 16 Sep.

  1. Apache ZooKeeper Flaws Let Attackers Delete Nodes and Spoof Logs
    SecurityOnline · first in our coverage · mentions it in passing

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References

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