CVE-2026-115448: Apache ZooKeeper: Unbounded recursion in snapshot serialization allows a client to render the server unrecoverable
Apache Software Foundation · Apache ZooKeeper
Vendor fix available · Affected: Apache Software Foundation Apache ZooKeeper · Exploitation: not established
ExploitationNot established
Not in CISA KEV as of catalogue 2026.11.04 (4 Nov)
- In CISA KEV: not seen
- Exploited (reported): not seen
- Scanning observed: not seen
- Proof of concept public: not seen
- Not establishedNothing in the sources we check
No EPSS score yet. The score appears once FIRST publishes it.
DescriptionNVD
Uncontrolled recursion in Apache ZooKeeper. The server serializes its data tree to a snapshot by recursing one stack frame per znode level, with no depth bound. A client permitted to create znodes (the default root ACL is open) can build a chain of nested znodes deep enough that taking a snapshot exhausts the JVM stack and kills the snapshot thread; sizes stay within jute.maxbuffer, so existing limits do not prevent it. This is a denial of service that becomes persistent: on restart the server rebuilds the deep tree from its transaction log and fails again while taking the startup snapshot, so it does not return to service, and recovery can entail data loss. The same log affects a leader and its followers, so it can spread across an ensemble. This issue affects Apache ZooKeeper 3.8.0 through 3.8.7 and 3.9.0 through 3.9.6. Users are recommended to upgrade to 3.8.8 or 3.9.7, which fix the issue. As a workaround, use ACLs and authentication to restrict znode creation rather than relying on the default open root ACL.
Coverage1 article · 1 outlet
First in our coverage: SecurityOnline, 5 Nov.
- Apache fixes flaws across ZooKeeper, OpenOffice and ActiveMQSecurityOnline · first in our coverage
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