CVE-2026-53416

Executive Summary

CVE-2026-53416 is a path traversal vulnerability (CWE-23) in the Zoom VDI Client and associated plugins. It allows an authenticated user with local access to the system to disclose information outside of expected directory boundaries, potentially gaining access to sensitive files. The vulnerability has a CVSS score of 7.1 (High) with high confidentiality and integrity impact but no availability impact. As of this report, no public exploit or patch exists, and the CVE is not listed on the CISA Known Exploited Vulnerabilities catalog.

Technical Analysis

The NVD description provides limited implementation detail but identifies the flaw as a path traversal vulnerability residing in the Zoom VDI Client and its plugins. Path traversal (CWE-23) is a file-handling flaw where an application fails to validate or sanitize file paths supplied by the user, permitting an attacker to reference files or directories outside the application's intended scope. In the context of a VDI (Virtual Desktop Infrastructure) client, this typically means the client process has access to the local host filesystem while abstracting that filesystem through a remote session.

The vulnerability is characterized by:

• Attack Vector: Local (AV:L) — The attacker must be authenticated on the local system, or in a position where they control local input to the client.
• Attack Complexity: Low (AC:L) — No special conditions or race conditions are required to exploit the flaw.
• Privileges Required: Low (PR:L) — A standard authenticated user account is sufficient.
• User Interaction: None (UI:N) — The victim does not need to perform any action beyond the exploitation sequence.

The information disclosure (confidentiality impact: High) suggests that arbitrary file read is possible — likely readable files from the host system. The integrity impact (High) implies the traversal may also permit overwriting files outside the intended sandbox, although the description explicitly emphasizes disclosure. The absence of availability impact (A:N) suggests the flaw does not permit denial of service.

The attack surface is the Zoom VDI Client, which brokers connections between a local endpoint and a hosted virtual desktop. The plugins referenced extend functionality but appear to inherit the same file-handling flaw. Since VDI software routinely handles file transfers, screen captures, and content redirection between local and remote environments, the traversal likely exists in a routine that maps or transfers local files into the remote session without proper path canonicalization.

Insufficient technical detail is available in the NVD description to identify specific function names, URL endpoints, or file paths. The attack mechanism, however, is classically that of an unvalidated file path input (e.g., a filename parameter in a file-transfer routine) that allows ../ sequences to escape the intended base directory.

Exploitation Scenarios

No public PoC is available; the attack chain is inferred from the vulnerability class (path traversal).

Step 1 — Reconnaissance / Target Identification:
An attacker with a local authenticated session on a machine running the Zoom VDI Client identifies the client process and its associated file-handling capabilities. The attacker may inspect the Zoom VDI installation directory and plugin manifest files to identify which components perform file access operations. The target of interest is typically a document repository located on the user's local machine, such as SSH keys, credentials, configuration files, or browser-stored data.

Step 2 — Triggering the Flaw:
The attacker interacts with the Zoom VDI Client in a way that causes it to accept a file path as input — for example, initiating a file-transfer operation, or invoking a plugin function that takes a file name or path argument. Because user-supplied paths are not validated, the client passes the path to a filesystem API without canonicalization, allowing the attacker to supply a path like ..\..\..\Windows\System32\config\SAM or similar traversal sequences.

Step 3 — Payload / Execution Method:
The attack is performed entirely through valid, local interactions with the VDI client. No remote payload delivery is required. The attacker provides a malformed file path containing traversal sequences (../) that, when processed by the client, resolve outside the intended base directory. The client then accesses the resolved path and returns the file contents — either to the attacker directly or into the remote VDI session that the attacker controls.

Step 4 — Post-Exploitation Impact:
Successful exploitation allows the attacker to read arbitrary files on the local file system subject to the privileges of the user account running the Zoom VDI Client. This could include configuration files, private keys (e.g., id_rsa), credential stores, and other sensitive documents. The high integrity impact suggests the attacker may also be able to overwrite files, potentially planting malicious files that would execute when accessed by the VDI session or other local applications, though the NVD description does not explicitly confirm write capability.

Impact Assessment

• Technical Impact: Arbitrary file read (and possibly file write) on the local host file system by a low-privileged authenticated user. Confidentiality impact is High; Integrity impact is High; Availability is unaffected.
• Business Impact: This vulnerability is of particular concern in enterprise VDI environments where Zoom VDI Client is deployed on managed endpoints. If a lower-privileged employee (or a compromised account) can access the files of a more privileged user on a shared workstation, that represents a lateral movement enabler and credential-theft vector. The low complexity and lack of user interaction make this a straightforward flaw to exploit once an authenticated session exists.
• Blast Radius: All deployments of Zoom VDI Client with the vulnerable file-handling logic. Given the absence of a version range, the blast radius is effectively "all current Zoom VDI Client installations in the wild," pending vendor patch release. EPSS score of 0.00170 (6.7th percentile) indicates low current exploitation prevalence.

Detection Guidance

Sigma Rule

title: Zoom VDI Client - Path Traversal File Access
status: experimental
description: Detects attempts to exploit CVE-2026-53416 path traversal in Zoom VDI Client via file access patterns.
author: Valtersit Threat Intelligence
logsource:
  category: process_creation
  product: windows
detection:
  selection_zoom:
    Image|endswith:
      - '\ZoomVDIClient.exe'
      - '\ZoomPlugins.exe'
  selection_traversal:
    CommandLine|contains:
      - '..\'
      - '..%5c'
      - '%2e%2e%2f'
  condition: selection_zoom and selection_traversal
falsepositives:
  - Legitimate administrative use of relative paths in troubleshooting contexts
level: high

YARA Rule

rule Zoom_VDI_Path_Traversal_CVE_2026_53416
{
    meta:
        author = "Valtersit Threat Intelligence"
        description = "Detects path traversal patterns in Zoom VDI Client execution or log artifacts"
        cve = "CVE-2026-53416"
        date = "2026-01-01"
    strings:
        $s1 = "../" ascii
        $s2 = "..\\" ascii
        $s3 = "%2e%2e%2f" ascii
        $s4 = "Zoom VDI" ascii nocase
        $s5 = "VDIClient" ascii nocase
    condition:
        (any of ($s1, $s2, $s3)) and (any of ($s4, $s5))
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-53416 - Zoom VDI Client Path Traversal Attempt"; flow:to_server,established; content:"|2e 2e 2f|"; sid:10053416; rev:1; reference:cve,CVE-2026-53416;)

Note: Suricata coverage applies primarily if the traversal is transmitted over a network tunnel (VDI connection). Local-only file operations may not produce network traffic; this rule addresses the remote-session scenario where traversal strings are sent to a server.

Elastic Detection

process where process.name : ("ZoomVDIClient.exe", "ZoomPlugins.exe") and
  process.command_line : (
    "*..\\*",
    "*..%5c*",
    "*%2e%2e%2f*"
  )

Splunk SPL Query

index=windows_process sourcetype=WinEventLog
  (Image="*ZoomVDIClient.exe*" OR Image="*ZoomPlugins.exe*")
  (CommandLine="*..\\*" OR CommandLine="*..%5c*" OR CommandLine="*%2e%2e%2f*")

Wazuh OSSEC Rule

<group name="zoom,">
  <rule id="741739" level="12">
    <if_sid>169</if_sid>
    <match>ZoomVDIClient|ZoomPlugins</match>
    <regex type="pcre2">(\.\.\\|\.\.%5c|%2e%2e%2f)</regex>
    <description>CVE-2026-53416: Path traversal attempt in Zoom VDI Client process arguments</description>
    <mitre>
      <id>T1204</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 0/4 — UNPATCHED. No patch evidence from any tracked source.

Immediate mitigations:

1. Restrict local user accounts to non-administrative privileges where possible; the flaw requires only low privileges to exploit but limiting filesystem access reduces the data exposed.
2. Apply file-system ACLs to sensitive directories (e.g., %USERPROFILE%\.ssh\, credential stores) to prevent the Zoom process account from accessing them even if the traversal succeeds.
3. Monitor and audit Zoom VDI Client process executions and file access logs on endpoints for anomalous traversal patterns.
4. If feasible in your environment, run Zoom VDI Client in a restricted sandbox or container that limits filesystem visibility.

Patch / upgrade steps:

1. Monitor Zoom's vendor advisory channels and update the Zoom VDI Client to the first patched version when released.
2. Subscribe to CVE feeds and Zoom's security notification list to receive immediate patch alerts.

Long-term hardening:

1. Maintain an up-to-date inventory of all Zoom VDI Client installations across the enterprise.
2. Implement least-privilege policies for local accounts, especially on shared or multi-user workstations.
3. Establish a formal vulnerability management SLA that prioritizes patching of VDI components (which are often overlooked relative to core server infrastructure).

References

1. NVD Entry: CVE-2026-53416 — NVD database record with CVSS vector and description.
2. Zoom Security Advisory Page — vendor advisories are expected to be published pending patch; no reference is currently available.
3. MITRE CWE-23 — Relative Path Traversal — weakness class describing path traversal vulnerabilities.
4. CISA Known Exploited Vulnerabilities Catalog — CVE-2026-53416 is NOT Listed — verified no exploitation in the wild.
5. FIRST EPSS — EPSS Score API — EPSS score of 0.00170 with 6.7% percentile, indicating low active exploitation probability.

No threat-actor campaigns or exploit-in-the-wild evidence are associated with CVE-2026-53416 at the time of this report.