CVE-2026-40106: Wazuh: Heap-based Buffer Overflow in syscheck Registry Wildcard Expansion (LPE / DoS)

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-07-17 · updated 2026-07-20
Weakness: CWE-122

Description

Wazuh is a free and open source platform used for threat prevention, detection, and response. Versions 4.6.0 and above prior to 4.14.5 contain a heap-based buffer overflow vulnerability in the syscheck component of the Wazuh agent for Windows. When expanding registry paths containing wildcards (* or ?), the agent allocates a fixed-size heap buffer of 256 bytes (OS_SIZE_256). By creating a registry subkey with a maximum allowed length (255 characters) inside a monitored path, a low-privileged local attacker can force an out-of-bounds write during string concatenation. Since wazuh-agent.exe runs as NT AUTHORITY\SYSTEM, this can lead to a silent Denial of Service (blinding the agent) or potentially Local Privilege Escalation (LPE). This issue has been fixed in version 4.14.5.

Affected products

wazuh: from 4.6.0 before 4.14.5 — fixed in 4.14.5

How to fix

Upgrade to a fixed version: wazuh 4.14.5. Check the vendor advisory for mitigations.

References

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