Public mode

No access to your tenant or devices. Every item links to its source. What this means

CVE-2026-84501

Apache ZooKeeper: Operational log forgery via newline injection in EnsembleAuthenticationProvider

cve-program · severity unknownCVSS unknownCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-84501

Published

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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-84501

Published

org.apache.zookeeper:zookeeper

https://repo.maven.apache.org/maven2

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "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"
                }

Original source record · Cite this exact observation · Complete original publisher JSON