CVE-2026-24281High· 7.4▾ TwilightHostname verification in Apache ZooKeeper ZKTrustManager falls back to reverse DNS (PTR) when IP SAN validation fails, allowing attackers who control or spoof PTR records to impersonate ZooKeeper servers or clients with a valid certifica…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 40.7 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 4.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.6%
Hostname verification in Apache ZooKeeper ZKTrustManager falls back to reverse DNS (PTR) when IP SAN validation fails, allowing attackers who control or spoof PTR records to impersonate ZooKeeper servers or clients with a valid certificate for the PTR name. It's important to note that attacker must present a certificate which is trusted by ZKTrustManager which makes the attack vector harder to exploit. Users are recommended to upgrade to version 3.8.6 or 3.9.5, which fixes this issue by introducing a new configuration option to disable reverse DNS lookup in client and quorum protocols.
zookeeper >= 3.8.0, < 3.8.6zookeeper >= 3.9.0, < 3.9.5Upgrade past the affected range:
zookeeper 3.9.5Connected by shared product, vendor, weakness, or advisory.
CVE-2026-24308High· 7.5Improper handling of configuration values in ZKConfig in Apache ZooKeeper 3.8.5 and 3.9.4 on all platforms allows an attacker to expose sensitive information stored in client configuration in the client's logfile
CVE-2026-84439Medium· 5.3When 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 us…
CVE-2026-59969High· 7.5Apache ZooKeeper quorum TLS fails to enforce peer hostname verification in FIPS-mode deployments
CVE-2026-79993High· 7.5The `deleteContainer` opcode (0x14/20) is processed without verifying the caller's ACL permissions, allowing any authenticated client to delete specific znodes in the data tree regardless of the ACL restrictions on the znode or its paren…
CVE-2026-59739High· 7.5Information disclosure via SetWatches reconnect replay in Apache ZooKeeper due to missing ACL check. An attacker can discover ACL-restricted paths by registering exists-watches on non-existent paths, then reconnecting after the paths are…
CVE-2026-84501Medium· 5.3An 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)