CVE-2026-44251: Wazuh Platform DoS Vulnerability

CVE-2026-44251 Overview

CVE-2026-44251 is an integer underflow vulnerability in Wazuh, an open source platform for threat prevention, detection, and response. The flaw exists in os_crypto/shared/msgs.c:389 and affects Wazuh versions 3.0.0 through 4.14.4. Any enrolled Wazuh agent can trigger a size_t underflow that crashes the wazuh-remoted process on the manager. The crash immediately disconnects every agent from the manager, disabling centralized monitoring. A secondary code path reached via the same underflow may lead to heap memory corruption [CWE-122]. Wazuh addressed the issue in version 4.14.5.

Critical Impact
An authenticated agent can crash the Wazuh manager's remote daemon, severing telemetry from all connected endpoints and potentially enabling heap corruption.

Affected Products

Wazuh versions 3.0.0 through 4.14.4
Wazuh Manager wazuh-remoted component
Deployments using enrolled agents communicating with a central manager

Discovery Timeline

2026-07-17 - CVE-2026-44251 published to NVD
2026-07-20 - Last updated in NVD database

Technical Details for CVE-2026-44251

Vulnerability Analysis

The vulnerability resides in the message-handling logic within os_crypto/shared/msgs.c at line 389. Wazuh uses this code path to parse encrypted messages sent by enrolled agents to the manager's wazuh-remoted daemon. A size_t variable, which is an unsigned integer type, undergoes an arithmetic operation that produces a value below zero. Because size_t cannot represent negative values, the result underflows and wraps to a very large positive integer.

When this corrupted length value propagates through subsequent processing, wazuh-remoted terminates unexpectedly. Every agent connected to the manager loses its session at the moment of the crash. A second code path reached via the same underflow may permit heap memory corruption, expanding the impact beyond denial of service [CWE-122].

Root Cause

The root cause is missing validation of an input-derived length value before it is used in unsigned arithmetic. Any enrolled agent supplies attacker-controlled data that reaches this calculation. Without a bounds check, the operation underflows the size_t and produces an oversized length that downstream code treats as valid.

Attack Vector

Exploitation requires the attacker to control an enrolled Wazuh agent. This includes compromised endpoints already running the agent or an attacker with valid enrollment credentials. The malicious agent transmits a crafted message to the manager over the standard agent-to-manager channel. The manager processes the message, triggers the underflow in msgs.c, and either crashes wazuh-remoted or reaches the heap corruption code path. No user interaction on the manager is required.

No public proof-of-concept exploit is currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-44251

Indicators of Compromise

Unexpected termination or repeated restarts of the wazuh-remoted process on the manager
Simultaneous disconnection of all agents recorded in manager logs
Malformed or oversized agent messages appearing in ossec.log prior to a crash
Core dumps or segmentation faults associated with wazuh-remoted

Detection Strategies

Monitor wazuh-remoted process health and alert on unexpected exits or restart loops
Correlate mass agent disconnection events with manager service state changes
Inspect ossec.log and remoted.log for parsing errors immediately preceding a service outage
Track agents that repeatedly trigger message-handling errors as potential sources of exploitation

Monitoring Recommendations

Alert on any single agent generating anomalous message volume or malformed payloads toward the manager
Baseline normal wazuh-remoted memory usage and flag deviations that could indicate heap corruption
Forward Wazuh manager logs to a centralized SIEM for correlation with endpoint activity

How to Mitigate CVE-2026-44251

Immediate Actions Required

Upgrade all Wazuh managers to version 4.14.5 or later, which contains the fix
Audit enrolled agents and revoke enrollment keys for any endpoints that are decommissioned or suspect
Restrict network access to the manager's agent communication port (default TCP 1514) to known agent subnets
Review manager logs for prior instances of wazuh-remoted crashes that may indicate earlier exploitation attempts

Patch Information

Wazuh released version 4.14.5 to remediate CVE-2026-44251. The fix corrects the integer handling in os_crypto/shared/msgs.c so that untrusted length values are validated before use. Full technical details are available in the Wazuh GitHub Security Advisory GHSA-jv5r-5p7c-g9fq.

Workarounds

No official workaround eliminates the vulnerability without upgrading; apply the 4.14.5 patch as the primary remediation
Limit which hosts can enroll as agents and enforce strict enrollment key management to reduce the attacker population
Segment the manager on a dedicated network and apply firewall rules that permit only trusted agent sources
Enable automated service supervision so wazuh-remoted restarts quickly if crashed while patching is in progress

bash

# Upgrade Wazuh manager on Debian/Ubuntu to the patched release
apt-get update
apt-get install --only-upgrade wazuh-manager=4.14.5-1
systemctl restart wazuh-manager

# Verify the running version
/var/ossec/bin/wazuh-control info | grep WAZUH_VERSION