CVE-2026-25770: Wazuh Privilege Escalation Vulnerability

CVE-2026-25770 Overview

CVE-2026-25770 is a privilege escalation vulnerability affecting the Wazuh security platform's cluster synchronization protocol. This vulnerability allows authenticated cluster nodes to write arbitrary files to the manager's file system, ultimately enabling root-level remote code execution through configuration file manipulation.

The vulnerability exists in the wazuh-clusterd service, which permits authenticated nodes to overwrite critical configuration files including /var/ossec/etc/ossec.conf. By injecting malicious <localfile> command blocks into this configuration, attackers can leverage the wazuh-logcollector service—which executes with root privileges—to achieve full system compromise.

Critical Impact

Authenticated attackers with cluster credentials can achieve full root remote code execution on Wazuh Manager servers, completely bypassing the platform's security model and violating the principle of least privilege.

Affected Products

• Wazuh versions 3.9.0 through 4.14.2
• Wazuh Manager cluster deployments with multiple nodes
• Systems running wazuh-clusterd and wazuh-logcollector services

Discovery Timeline

• 2026-03-17 - CVE CVE-2026-25770 published to NVD
• 2026-03-19 - Last updated in NVD database

Technical Details for CVE-2026-25770

Vulnerability Analysis

This vulnerability chains together multiple security weaknesses to achieve root-level remote code execution. The attack flow begins with the cluster synchronization protocol's overly permissive file write capabilities. When a node joins a Wazuh cluster, it communicates with the manager through the wazuh-clusterd service, which handles file synchronization between cluster members.

The core issue stems from insecure default file permissions where the wazuh system user—used by the cluster service—has write access to /var/ossec/etc/ossec.conf, the manager's primary configuration file. This configuration should be protected from modification by non-root services.

An attacker who has obtained valid cluster credentials can exploit the cluster protocol to overwrite the ossec.conf file with a malicious version. This malicious configuration includes injected <localfile> blocks containing arbitrary commands. The wazuh-logcollector service, which runs as root and monitors log sources defined in the configuration, parses these injected blocks and executes the embedded commands with full root privileges.

Root Cause

The root cause is classified as CWE-22 (Path Traversal), combined with insecure default permissions on critical configuration files. The cluster synchronization protocol fails to properly validate and restrict file paths that authenticated nodes can write to, allowing traversal to sensitive system configuration files. Additionally, the wazuh service user has excessive write permissions to the main configuration file, enabling the privilege escalation chain.

Attack Vector

The attack vector is network-based and requires authentication with valid cluster credentials. An attacker must first compromise or obtain credentials for a cluster node. Once authenticated to the cluster, the attacker leverages the cluster synchronization protocol to write a modified ossec.conf file to the manager. The injected configuration exploits the trust relationship between the configuration file and the root-privileged wazuh-logcollector service.

The attack chain proceeds as follows: the attacker authenticates to the cluster service, crafts a malicious configuration file containing command injection in a <localfile> block, uses the cluster protocol's file write functionality to overwrite the manager's configuration, and waits for the wazuh-logcollector service to reload and execute the injected commands as root.

Detection Methods for CVE-2026-25770

Indicators of Compromise

• Unexpected modifications to /var/ossec/etc/ossec.conf file, particularly new or unusual <localfile> entries
• Suspicious file write operations from the wazuh-clusterd process targeting configuration files
• Unusual cluster synchronization traffic patterns or unexpected file synchronization requests
• Evidence of command execution from the wazuh-logcollector process that doesn't match expected log collection activities

Detection Strategies

• Implement file integrity monitoring (FIM) on /var/ossec/etc/ossec.conf and other critical Wazuh configuration files
• Monitor wazuh-clusterd service logs for unusual file write operations or unexpected cluster node authentication attempts
• Deploy process monitoring to detect unexpected child processes spawned by wazuh-logcollector
• Review cluster authentication logs for unauthorized or anomalous node connections

Monitoring Recommendations

• Enable audit logging for all file modifications within /var/ossec/etc/ directory
• Configure alerts for any changes to ossec.conf that occur outside of scheduled maintenance windows
• Monitor network traffic to and from the cluster service port for unusual patterns or volumes
• Implement behavioral analysis for the wazuh-logcollector process to detect command execution anomalies

How to Mitigate CVE-2026-25770

Immediate Actions Required

• Upgrade Wazuh to version 4.14.3 or later immediately to address this vulnerability
• Review and audit current cluster node credentials for any signs of compromise
• Restrict file system permissions on /var/ossec/etc/ossec.conf to prevent write access by the wazuh service user where operationally feasible
• Implement network segmentation to limit access to cluster communication ports

Patch Information

Wazuh has released version 4.14.3 to address this vulnerability. The fix addresses the insecure default permissions and implements proper validation on cluster file synchronization operations to prevent arbitrary file writes. Organizations should upgrade all Wazuh Manager instances in their environment. For detailed information, refer to the GitHub Security Advisory GHSA-r4f7-v3p6-79jm.

Workarounds

• Restrict network access to the cluster service ports using firewall rules, limiting connections to only trusted and verified cluster nodes
• Implement additional authentication controls or mutual TLS for cluster communications
• Create backup copies of ossec.conf and implement automated integrity checking to detect unauthorized modifications
• Consider running single-node deployments without cluster functionality where multi-node architecture is not strictly required

# Restrict permissions on ossec.conf as a temporary mitigation
chmod 640 /var/ossec/etc/ossec.conf
chown root:wazuh /var/ossec/etc/ossec.conf

# Verify current permissions
ls -la /var/ossec/etc/ossec.conf

# Create backup for integrity verification
cp /var/ossec/etc/ossec.conf /var/ossec/etc/ossec.conf.backup
sha256sum /var/ossec/etc/ossec.conf > /var/ossec/etc/ossec.conf.sha256