CVE-2026-44253: Wazuh: Cluster Protocol Memory Exhaustion (DoS) via unbounded receive_str allocation and div_msg_box accumulation

Severity: medium (CVSS 4.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-08-19 · updated 2026-10-27
Weakness: CWE-770

Description

Wazuh is a free and open source platform used for threat prevention, detection, and response. From 3.9.0 until 4.14.5 and 5.0.0-beta2, the Wazuh cluster protocol in framework/wazuh/core/cluster/common.py allows an authenticated cluster node to exhaust memory on the master. The receive_str() method accepts an attacker-controlled total for InBuffer without a maximum, so a new_str command can request a multi-gigabyte bytearray and repeated requests accumulate in in_str. The divided-message path also retains flag_divided fragments under unique counters in div_msg_box without a count, aggregate-size, or expiration limit. Exploitation can disrupt agent connectivity and alert processing across the monitored environment. This issue is fixed in versions 4.14.5 and 5.0.0-beta2.

Affected products

wazuh: from 3.9.0 before 4.14.5; 5.0.0-beta1 — 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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