CVE-2026-34926: Trend Micro Apex One (On-Premise) Directory Traversal Vulnerability

Vulnerability summary

CVE-2026-34926 is a medium (CVSS 6.7) Relative Path Traversal vulnerability in Trend Micro Apex One. It is known to be exploited: CISA lists it, first on 21-05-2026. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.4% of scored vulnerabilities.

Timeline

1. 21-05-2026
   PublishedVulnerability first disclosed.
2. 21-05-2026
   Added to CISA KEVTrend Micro Apex One (On-Premise) Directory Traversal Vulnerability
3. 22-05-2026
   Last modifiedVulnerability information updated.
4. 04-06-2026
   CISA remediation dueApply mitigations per vendor instructions.

Description

A directory traversal vulnerability in the Apex One (on-premise) server could allow a pre-authenticated local attacker to modify a key table on the server to inject malicious code to deploy to agents on affected installations. This vulnerability is only exploitable on the on-premise version of Apex One and a potential attacker must have access to the Apex One Server and already obtained administrative credentials to the server via some other method to exploit this vulnerability.

• CWE-23Relative Path TraversalThe product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.