CVE-2026-71540— Wazuh Manager cluster header parsing allows pre-authentication memory exhaustion
Quick assessment
Affected
wazuh wazuh
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Wazuh 是一个开源安全平台，为终端和云工作负载提供统一的 XDR（扩展检测与响应）和 SIEM（安全信息与事件管理）保护。从版本 3.9.0 到 4.14.7，在 framework/wazuh/core/cluster/common.py 中的 wazuh-clusterd 模块存在一个漏洞：在通过 Fernet 解密验证对等方身份之前，系统会根据 20 字节的集群协议头中声明的大小分配一个 payload（有效载荷）缓冲区。未认证的网络对等方可以声明高达 256 MiB 的 payload 大小，在发送完头
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I. Basic Information for CVE-2026-71540
Vulnerability Information
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Vulnerability Title
Wazuh Manager cluster header parsing allows pre-authentication memory exhaustion
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-71540
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Other References for CVE-2026-71540 (4)
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Release Wazuh v4.14.7 · wazuh/wazuh · GitHub x_refsource_MISC
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V. Comments for CVE-2026-71540
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