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CISA KEVmediumPath Traversalpublic exploit

CVE-2026-34926

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

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.

Published Updated Sources: NVD, Trend Micro, Inc. (CNA), CISA, FIRST EPSS, GitHub, GitHub Security Advisory, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed May 21, 2026

EPSS

1%

ahead of 43% of scored CVEs

Affects

Trend Micro, Inc.

2 products listed

CVSS base

6.7

medium

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

No

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade TrendAI Apex One to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

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.

Federal deadline Jun 4, 2026 — passed 122 days ago

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

  • Identify exposed assets running affected vendor/product/version combinations.
  • Treat as emergency remediation because CISA KEV status is present.
  • Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

VendorProductVersionsStatus
Trend Micro, Inc.TrendAI Apex One2019 (14.0) to < 14.0.0.17079Vulnerable
Trend Micro, Inc.TrendAI Apex One as a ServiceSaaS to < 14.0.20731Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

Low

Confidentiality

High

Integrity

Low

Scope

Changed

Attack Complexity

High

Attack Vector

Local

Privileges Req

High

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
6.7CVSS 3.1medium0.85.3Trend Micro (ZDI) (CNA), Trend Micro, Inc. (CNA), GHSA

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:L/A:L

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-23 · Relative Path Traversal

  • Execute Unauthorized Code or Commands
  • Modify Files or Directories
  • Read Files or Directories
  • DoS: Crash, Exit, or Restart

Mitigation: Assume all input is malicious. Use an accept known good input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, boat may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as red or blue. Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single . character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as / to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering / is insufficient protection if the filesystem also supports the use of as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if ../ sequences are removed from the .../...// string in a sequential fashion, two instances of ../ would be removed from the original string, but the remaining characters would still form the ../ string.

Weakness & attack patterns

  • CWE-23

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-139 · Relative Path TraversalCAPEC-76 · Manipulating Web Input to File System Calls

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

May 21, 2026

Federal deadline

Jun 4, 2026

passed 122 days ago

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

8

1 of the 5 sampled are weaponized

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

SOCRadar29 more posts on this CVEShowing 5 of 34 · Who is discussing this CVE, and how loudlyUnlock free

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Monitor for scanner or exploit-pattern traffic after 8 public PoC repositories were reported.

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

  1. 2026

  2. Added · CVSS 3.1 6.7 (AV:L)

    Jul 23, 2026 · NVD

  3. Added to CISA KEV catalog

    May 21, 2026 · CISA

  4. Initial · CVE published

    May 21, 2026 · NVD

  5. Added · GHSA-4ccp-cqrh-3w9v published (medium)

    May 21, 2026 · GitHub Security Advisory

Source activity

Readings a source repeats on a schedule, counted rather than listed.

  • 24×SvrsMay 22, 2026 – Jul 5, 2026 · SOCRadar CTI
  • 13×TweetsMay 23, 2026 – Jun 24, 2026 · SOCRadar CTI
  • 1×3 times mentioned on 2 Telegram channelsMay 26, 2026 · SOCRadar CTI
  • 1×Github_Repos · Github repository created, HORKimhab/CVE-2026-34926May 22, 2026 · SOCRadar CTI

References

7 on the record

Coverage

16 stories from the feeds we poll

SOCRadar11 more reports on this CVEShowing 5 of 16 · Vendor research and security press coverageUnlock free

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1

What should defenders know first?

CVE-2026-34926 is Trend Micro Apex One (On-Premise) Directory Traversal Vulnerability, a medium vulnerability affecting TrendAI Apex One, TrendAI Apex One as a Service from Trend Micro, Inc.. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 8 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 6.7 describes technical severity, while EPSS 1% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.