CVE-2026-40106 Wazuh: Heap-based Buffer Overflow in syscheck Registry Wildcard Expansion (LPE / DoS)
A heap-based buffer overflow in the Wazuh Windows agent allows local attackers to cause denial of service or escalate privileges via registry wildcard expansion.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-40106?
CVE-2026-40106 is a medium-severity memory corruption vulnerability in Wazuh Wazuh, published on 16 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-122
Which versions are affected by CVE-2026-40106?
It affects 1 product.
Products include Wazuh Wazuh.
How do I fix CVE-2026-40106?
No fix has been published for CVE-2026-40106 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-40106 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40106 exists.
Other vulnerabilities in Wazuh Wazuh
- CVE-2025-24016 Wazuh Server Deserialization of Untrusted Data
- CVE-2024-32038 Wazuh Analysis Engine Event Decoder Heap-based Buffer Overflow Remote Code Execution Vulnerability
- CVE-2021-44079 Command injection in n/a
- CVE-2024-1243 Remote code execution and local privilege escalation in Wazuh Windows agent via NetNTLMv2 hash theft
- CVE-2026-61800 Wazuh cluster worker file sync allows arbitrary file write under /var/ossec (incomplete fix for CVE-2026-30893)
Sources
Also known as GHSA-qvrc-pcfc-jhqc.