CVE-2026-44253 Wazuh: Cluster Protocol Memory Exhaustion (DoS) via unbounded receive_str allocation and div_msg_box accumulation
An authenticated cluster node can exhaust master memory via unbounded allocations, disrupting agent connectivity and alert processing in Wazuh deployments.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-44253?
CVE-2026-44253 is a medium-severity denial of service vulnerability in Wazuh Wazuh, published on 19 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-44253?
It affects 1 product.
Products include Wazuh Wazuh.
How do I fix CVE-2026-44253?
No fix has been published for CVE-2026-44253 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-44253 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44253 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-h5r8-gvhv-cmp2.