Security Digest · Vulnerability record · Known exploited
CVE-2026-34926: Trend Micro Apex One (On-Premise) Directory Traversal Vulnerability
Exploited in the wild (CISA KEV). 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.
CISA KEV · added 2026-05-21 CVSS 6.7 Medium EPSS 0.5% · p44
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run Trend Micro Apex One. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-05-21, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-06-04; treat that as the outer limit, not the target.
- EPSS 0.5%, percentile 44: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 44% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
What it is
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.
CISA’s summary
Trend Micro Apex One (on-premise) contains a directory traversal vulnerability that 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.
Weakness type: CWE-23.
Product: Trend Micro Apex One · Assigned by: trendmicro · Published: 2026-05-21
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Trend Micro, Inc. | TrendAI Apex One | 2019 (14.0) < 14.0.0.17079 |
| Trend Micro, Inc. | TrendAI Apex One as a Service | SaaS < 14.0.20731 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| trendmicro | 3.1 | 6.7 Medium | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:L/A:L |
- Attack vector: local access needed
- Attack complexity: high (needs special conditions)
- Privileges required: high (admin)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2026-05-21; federal due date 2026-06-04. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.54% probability of exploitation activity in the next 30 days; percentile 44.
Timeline
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CVE record published by trendmicro
- — CVE record last updated
- — CISA remediation deadline for US federal agencies
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- Listed in CISA KEV notes (success.trendmicro.com) success.trendmicro.com
Vulnerability records
- CVE.org record CVE-2026-34926 cve.org
- NVD entry CVE-2026-34926 nvd.nist.gov
Government
Other references from the CVE record and advisory
- success.trendmicro.com success.trendmicro.com
- jvn.jp jvn.jp
- jpcert.or.jp jpcert.or.jp
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