CVE-2026-40106
MEDIUMWazuh: Heap-based Buffer Overflow in syscheck Registry Wildcard Expansion (LPE / DoS)
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.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-40106 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-40106 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-40106. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-40106 in your dependencies?
O3 detects CVE-2026-40106 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.