# CVE-2026-71540: Wazuh unauthenticated memory exhaustion in cluster listener

Source: https://junglewise.ai/threats/cve-2026-71540-wazuh-is-an-open-source-security-platform-providing-unified-xdr  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-24. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-71540 · Severity: high · CVSS 7.5 · Published 2026-09-24

Wazuh is an open-source security platform that monitors endpoints and cloud workloads for threats. An unauthenticated remote attacker can exhaust memory on a Wazuh cluster node by opening multiple connections and declaring large payloads without sending the data, causing the cluster process to crash and disrupting security monitoring and threat detection across the organization.

Technologies: [Wazuh](https://junglewise.ai/threats/technologies/wazuh). Vendors: [Wazuh](https://junglewise.ai/threats/vendors/wazuh).

## Quick answers

**Is CVE-2026-71540 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-71540 being exploited in the wild.

**How severe is CVE-2026-71540?** High severity, with a CVSS score of 7.5, published 24 September 2026.

**Which products and versions are affected?** Wazuh 3.9.0 to 4.14.6.

**Is there a fix for CVE-2026-71540?** A patch was published on 2026-06-30: Fix committed; version 4.14.7 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-71540 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-71540?** Check whether you run Wazuh at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the cluster listener's payload buffer allocation logic in wazuh-clusterd. An unauthenticated network peer can craft a cluster protocol header declaring a payload up to 256 MiB and terminate the connection without sending the data, causing the full buffer to remain allocated until the TCP connection closes. The lack of per-source connection budgets allows an attacker to multiply memory consumption via concurrent sockets, leading to denial of service. The fix defers buffer allocation until data arrives and implements per-source-IP connection limits and payload completion deadlines.

## Affected products

- Wazuh Wazuh 3.9.0 to 4.14.6

## Timeline

- 2026-09-24: disclosed
- 2026-06-30: patched: Fix committed; version 4.14.7 released

## References

- [https://github.com/wazuh/wazuh/commit/9a996bc23d28725f6c1f8f7808355d90e20d3382](https://github.com/wazuh/wazuh/commit/9a996bc23d28725f6c1f8f7808355d90e20d3382)
- [https://github.com/wazuh/wazuh/pull/37280](https://github.com/wazuh/wazuh/pull/37280)

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