External risk intelligence

SonicWall GMS Unauthenticated File Read Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-109593

SonicWall GMS (Global Management System) is typically deployed as a centralized management and monitoring gateway for network infrastructure. These systems are often positioned at the network edge or in accessible segments to allow for administrative connectivity and monitoring, making them commonly reachable in environments where network management services are exposed.

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory concerns a vulnerability in SonicWall Global Management System (GMS) versions prior to 9.5.2 that could allow an unauthenticated attacker to read internal files over the network. The primary concern is confirming if this system is in use and assessing potential exposure.

Unauthenticated access can read sensitive internal files.
Centralized management systems are often network-accessible.
Confirm relevance and exposure of SonicWall GMS.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker could remotely access the SonicWall GMS system over the network. By leveraging this access, the attacker could target a vulnerability allowing them to read internal GMS files. This could expose sensitive information and potentially disrupt system operations.

Network access is required.
Internal GMS files can be read.
Sensitive data exposure is possible.

Live Threat

Current exploitation, exposure, and threat context

An unauthenticated attacker with network access could read internal GMS files, potentially exposing sensitive information. This may occur when the affected SonicWall GMS is accessible over the network.

Internal GMS files.
Network access to GMS.
Exposure of sensitive information.

Operational Fix

Recommended remediation, mitigation, and detection steps

Real-World Ownership

This vulnerability affects SonicWall GMS, a centralized management system for network infrastructure. The first practical step is to identify all GMS deployments, assess their exposure and business criticality, and confirm the accountable owner. Once identified, remediation should be planned based on the assessed risk.

Network and Security teams own the issue.
Verify GMS reachability and criticality.
Plan remediation based on risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

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Frequently asked questions

What is SonicWall GMS?

SonicWall GMS, or Global Management System, is a software platform designed for centralized oversight and monitoring of network infrastructure. It acts as a command-and-control hub, allowing administrators to manage multiple network devices—like firewalls or secure gateways—from a single interface. Because it is used to maintain visibility across an entire network, it is often deployed in positions that require broad connectivity to communicate with various internal components.

What does CWE-636 mean for CVE-2026-109593?

This vulnerability is classified as CWE-636, which refers to the 'not properly controlling the inclusion of configuration or data files' weakness. In the context of CVE-2026-109593, this means the software fails to correctly restrict access to its own internal files. An attacker can exploit this logic flaw to request and view files they should not have permission to access, effectively bypassing standard authentication requirements.

How can an attacker trigger this file read bug?

An attacker triggers the vulnerability by sending specially crafted requests over the network to a vulnerable SonicWall GMS instance. The flaw does not require the attacker to have valid credentials or prior login access to the system. However, this does not mean the bug can be triggered from anywhere; it specifically requires network-level reachability to the GMS service. If the system is strictly isolated from the network, the attack path is effectively blocked.

Is my instance relevant according to Halo Surface Signal?

Halo Surface Signal indicates that SonicWall GMS is often deployed at the network edge or in accessible segments to facilitate administrative monitoring. If your instance is reachable over the network—especially if it faces the internet—it is considered to have a higher potential for exposure. You should prioritize assessing systems that are positioned to be reachable by external or untrusted network traffic.

What should I do first to address this CVE?

Start by identifying all instances of SonicWall GMS running version 9.5.2 or earlier within your infrastructure. Once you have a complete list, verify the network reachability for each deployment to determine which are exposed. Assign ownership of these systems to your network or security teams, and document their business criticality to help prioritize your remediation plan while awaiting official updates.

References

psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0019

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.