5.3

CVE-2026-84501

Apache ZooKeeper: Operational log forgery via newline injection in EnsembleAuthenticationProvider

An unauthenticated attacker can inject arbitrary fake log lines into Apache ZooKeeper's operational log by sending a crafted add_auth("ensemble", ...) request containing newline characters (\n). When the ensemble name doesn't match, EnsembleAuthenticationProvider.handleAuthentication() logs the raw, unsanitized name via LOG.warn(). Because SLF4J's {} placeholder preserves embedded newlines, the attacker can forge complete log entries — with arbitrary timestamps, log levels, class names, and messages — that are visually indistinguishable from genuine ZooKeeper log output.

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 upgrade to version 3.8.7 or 3.9.6, which fixes the issue.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Apache ≫ Zookeeper Version >= 3.8.0 < 3.8.7
Apache ≫ Zookeeper Version >= 3.9.0 < 3.9.6
VulnDex Vulnerability Enrichment
Diese Information steht angemeldeten Benutzern zur Verfügung. Login Login
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.23% 0.134
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
CISA-ADP 5.3 3.9 1.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CWE-117 Improper Output Neutralization for Logs

The product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file.

https://lists.apache.org/thread/ohby1g6zjt72p0w79rhbr41nczzvr33y
Vendor Advisory
Mailing List
http://www.openwall.com/lists/oss-security/2026/09/15/7
Mailing List