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CVE-2026-44253 wazuh CVE debrief

A memory exhaustion vulnerability exists in Wazuh cluster protocol versions from 3.9.0 until 4.14.5 and 5.0.0-beta2. An authenticated cluster node can exploit this by sending a new_str command with an attacker-controlled total for InBuffer, causing the master to exhaust memory. This can disrupt agent connectivity and alert processing across the monitored environment.

Vendor
wazuh
Product
Unknown
CVSS
MEDIUM 4.9
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-19
Original CVE updated
2026-09-22
Advisory published
2026-08-19
Advisory updated
2026-09-22

Who should care

Wazuh users and administrators should assess their exposure and prioritize patching or mitigating this vulnerability to prevent potential disruption of agent connectivity and alert processing.

Why it matters

This vulnerability allows an authenticated cluster node to exhaust memory on the master, potentially disrupting agent connectivity and alert processing. Wazuh users and administrators should assess their exposure and prioritize patching or mitigating this vulnerability.

  • Disruption of agent connectivity
  • Disruption of alert processing
  • Potential for denial of service
  • Need for verification of patch deployment

Technical summary

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, and the divided-message path retains flag_divided fragments under unique counters in div_msg_box without a count, aggregate-size, or expiration limit. This issue can disrupt agent connectivity and alert processing across the monitored environment, and defenders should prioritize patching or mitigating this vulnerability.

Defensive priority

Defenders should prioritize patching or mitigating this vulnerability to prevent potential disruption of agent connectivity and alert processing.

Recommended defensive actions

  • Patch Wazuh to version 4.14.5 or 5.0.0-beta2
  • Restrict access to the Wazuh cluster protocol
  • Monitor Wazuh cluster nodes for unusual activity
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is caused by the receive_str() method in framework/wazuh/core/cluster/common.py, which accepts an attacker-controlled total for InBuffer without a maximum. The divided-message path also retains flag_divided fragments under unique counters in div_msg_box without a count, aggregate-size, or expiration limit.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-44253 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-44253

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-44253 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-44253

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.