CVE-2026-92905: ManageEngine EventLog Analyzer DoS Flaw

CVE-2026-92905 Overview

CVE-2026-92905 is a denial-of-service vulnerability affecting ZohoCorp ManageEngine EventLog Analyzer and Log360 builds prior to 13071. An unauthenticated remote attacker can crash the log collector process by sending malformed syslog packets to the affected service. The flaw is classified as an uncaught exception [CWE-248] and impacts log ingestion availability. Successful exploitation disrupts centralized logging, which can mask subsequent malicious activity across monitored environments.

Critical Impact
Remote, unauthenticated attackers can crash the syslog collector in EventLog Analyzer and Log360, interrupting log ingestion and reducing visibility into security events across the environment.

Affected Products

ZohoCorp ManageEngine EventLog Analyzer (builds before 13071)
ZohoCorp ManageEngine Log360 (builds before 13071)
Deployments exposing the syslog listener to untrusted networks

Discovery Timeline

2026-09-24 - CVE CVE-2026-92905 published to NVD
2026-09-24 - Last updated in NVD database

Technical Details for CVE-2026-92905

Vulnerability Analysis

The vulnerability resides in the syslog collector component of ManageEngine EventLog Analyzer and Log360. The collector parses inbound syslog messages received over the network. Malformed packets trigger an uncaught exception that terminates the collector process. Once the collector crashes, syslog ingestion halts until the service is restarted.

The impact is limited to availability. The flaw does not expose data or allow code execution. However, log collection outages weaken detection and response workflows, since security events arriving during the outage are dropped or delayed.

Root Cause

The root cause is an improperly handled exception [CWE-248] in the syslog parsing logic. The parser does not validate structural edge cases in incoming syslog payloads. When the parser encounters unexpected input, the exception propagates and crashes the collector thread rather than being caught and logged.

Attack Vector

The attack vector is network-based and does not require authentication or user interaction. An attacker sends a crafted syslog packet to the UDP or TCP syslog port the collector listens on. The malformed structure triggers the parsing fault, causing the collector to crash. Any host able to reach the syslog listener can execute the attack, including spoofed sources over UDP.

No verified public exploitation code is available. For technical specifics, consult the ManageEngine Security Advisory CVE-2026-92905.

Detection Methods for CVE-2026-92905

Indicators of Compromise

Unexpected termination or restart of the EventLog Analyzer or Log360 syslog collector service
Gaps in syslog ingestion timelines not correlated with maintenance windows
Inbound syslog traffic from unknown or spoofed source IP addresses preceding collector crashes
Exceptions related to syslog parsing in ManageEngine application logs

Detection Strategies

Monitor collector process uptime and alert on unexpected restarts of the syslog service
Baseline normal syslog ingestion rates and alert on sudden drops to zero
Inspect inbound syslog packets for malformed headers or non-RFC 3164/5424 conformant structures at the network boundary
Correlate collector crashes with inbound packet captures to identify suspect source addresses

Monitoring Recommendations

Enable health monitoring on the ManageEngine syslog listener and forward status events to a secondary SIEM
Deploy network flow monitoring on syslog ports (UDP/514, TCP/514, or configured alternates) for anomalous spikes
Retain packet captures on the syslog interface to support post-incident analysis of crash-inducing payloads

How to Mitigate CVE-2026-92905

Immediate Actions Required

Upgrade EventLog Analyzer and Log360 to build 13071 or later
Restrict network access to the syslog collector port to known, trusted log sources only
Verify collector service health and configure automatic restart on failure as an interim safeguard
Review historical ingestion gaps to identify prior exploitation attempts

Patch Information

ZohoCorp has addressed the issue in build 13071 of ManageEngine EventLog Analyzer and Log360. Administrators should apply the vendor-supplied update through the standard ManageEngine upgrade process. Refer to the ManageEngine Security Advisory CVE-2026-92905 for build details and upgrade procedures.

Workarounds

Apply firewall or ACL rules to permit syslog traffic only from authorized collectors and network devices
Place the syslog listener behind a syslog relay or proxy that validates and normalizes incoming messages
Enable service watchdog mechanisms to automatically restart the collector if it terminates unexpectedly

bash

# Example iptables rule to restrict syslog ingress to approved sources
iptables -A INPUT -p udp --dport 514 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 514 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p udp --dport 514 -j DROP
iptables -A INPUT -p tcp --dport 514 -j DROP