Buffer overflow in Wazuh
CVE-2026-40106
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.001 (2.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 2.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
- Wazuh — versions >= 4.6.0, < 4.14.5
Weakness classification (CWE)
References
- github.com/wazuh/wazuh/security/advisories/GHSA-qvrc-pcfc-jhqc (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-40106?
- CVE-2026-40106 is a medium-severity vulnerability in Wazuh, classified under Heap-based Buffer Overflow. CVSS score: 4.7/10. Published 2026-07-17.
- How severe is CVE-2026-40106?
- Medium severity. CVSS v3 base score is 4.7 out of 10.