CVE-2026-7490: Sunnet CTMS & CPAS RCE Vulnerability

CVE-2026-7490 Overview

CVE-2026-7490 is an arbitrary file upload vulnerability affecting Sunnet's Course and Training Management System (CTMS) and Course Performance Assessment System (CPAS). The flaw allows authenticated attackers with privileged accounts to upload web shell backdoors to the server. Once uploaded, attackers can execute the shells to achieve arbitrary code execution in the application context. The weakness maps to [CWE-434: Unrestricted Upload of File with Dangerous Type]. TW-CERT published the advisory and incident report on May 2, 2026.

Critical Impact
Authenticated remote attackers can upload web shells to gain arbitrary code execution, leading to full compromise of confidentiality, integrity, and availability of the affected server.

Affected Products

Sunnet CTMS (Course and Training Management System)
Sunnet CPAS (Course Performance Assessment System)
Specific affected versions are listed in the TW-CERT Security Advisory

Discovery Timeline

2026-05-02 - CVE-2026-7490 published to NVD
2026-05-05 - Last updated in NVD database

Technical Details for CVE-2026-7490

Vulnerability Analysis

The vulnerability resides in the file upload functionality of Sunnet CTMS and CPAS. The application fails to enforce sufficient validation on uploaded file types, names, or content. An attacker authenticated with a privileged account can submit a server-executable file, such as a .jsp, .aspx, or .php web shell, through the standard upload interface.

Because the uploaded file is stored in a web-accessible directory and served by the application server, the attacker can request the file directly through HTTP. This triggers server-side execution of attacker-controlled code under the privileges of the web application process.

The Exploit Prediction Scoring System rates active exploitation likelihood at 0.212% as of May 7, 2026. The attack requires high privileges, but no user interaction, and is reachable over the network.

Root Cause

The root cause is missing or improperly implemented validation at the file upload handler. The application does not enforce an allowlist of safe extensions, validate MIME types against file content, or store uploads outside the web root. This combination permits dangerous file types and grants direct execution paths to those files.

Attack Vector

The attack proceeds over the network through the application's authenticated interface. An attacker first obtains or compromises a privileged account in CTMS or CPAS. The attacker then uses the upload feature to submit a web shell disguised as a permitted document type or with a server-executable extension. Finally, the attacker invokes the uploaded shell over HTTP to run commands, pivot internally, or exfiltrate data.

No verified public proof-of-concept code is available for this issue. Refer to the TW-CERT Incident Report for additional context.

Detection Methods for CVE-2026-7490

Indicators of Compromise

New or unexpected files with executable extensions (.jsp, .aspx, .php, .ashx) in CTMS or CPAS upload directories.
Outbound connections from the web application process to unfamiliar IP addresses or command-and-control infrastructure.
Privileged user accounts performing upload actions outside of normal business hours or from atypical source IPs.
Web server processes spawning shell interpreters such as cmd.exe, powershell.exe, /bin/sh, or /bin/bash.

Detection Strategies

Inspect web server access logs for POST requests to upload endpoints followed by GET requests to newly created files in the same path.
Hash-compare uploaded files against known web shell signatures and YARA rules for China Chopper, Behinder, Godzilla, and AntSword.
Apply file integrity monitoring on CTMS and CPAS upload directories to alert on creation of files with server-executable extensions.

Monitoring Recommendations

Forward web server, application, and authentication logs to a centralized SIEM and correlate upload activity with subsequent process execution events.
Monitor parent-child process chains where the application server spawns command interpreters or network utilities such as curl, wget, or nc.
Track privileged account sessions in CTMS and CPAS, alerting on session anomalies, geolocation changes, and credential reuse.

How to Mitigate CVE-2026-7490

Immediate Actions Required

Apply the vendor patch referenced in the TW-CERT Security Advisory as soon as it is available for your deployment.
Audit all privileged accounts in CTMS and CPAS, rotate credentials, and remove unnecessary administrative access.
Search upload directories for unauthorized files and remove any confirmed web shells, then perform full incident response on affected hosts.

Patch Information

Sunnet has coordinated remediation through TW-CERT. Administrators should consult the vendor advisory and the TW-CERT Incident Report to identify the fixed version applicable to their CTMS or CPAS installation. Apply the update in a test environment first, then promote to production after validating functionality.

Workarounds

Restrict access to CTMS and CPAS administrative interfaces using network segmentation, VPN, or IP allowlisting until patching is complete.
Configure the web server to deny execution of script extensions within upload directories using rules such as Options -ExecCGI or equivalent IIS handler mappings.
Enforce multi-factor authentication on all privileged accounts to reduce the risk of credential abuse leading to exploitation.
Deploy a web application firewall rule that blocks uploads of files containing executable script signatures or disallowed extensions.

bash

# Example: deny script execution in an Apache upload directory
<Directory "/var/www/ctms/uploads">
    Options -ExecCGI
    RemoveHandler .php .phtml .phar .jsp .aspx
    AddType text/plain .php .phtml .phar .jsp .aspx
    php_admin_flag engine off
</Directory>