CVE-2026-40076

OpenMRS Module Upload Vulnerable to Path Traversal (Zip Slip)

The endpoint POST /openmrs/ws/rest/v1/module is vulnerable to a path traversal (Zip Slip) attack. An authenticated attacker can upload a crafted .omod archive containing ZIP entries with directory traversal sequences. Upon automatic extraction by the server, the incomplete path validation in WebModuleUtil.startModule() fails to prevent entries such as web/module/../../../../malicious.jsp from being written outside the intended module directory. If the traversal target falls within the web application root (e.g., /usr/local/tomcat/webapps/openmrs/), the attacker achieves arbitrary file write and subsequent Remote Code Execution.

Notably, other extraction methods in the same codebase (ModuleUtil.expandJar(), TestInstallUtil.addZippedTestModules()) are properly protected with normalize().startsWith() checks, this vulnerability is an oversight where the same fix was not applied.

Furthermore, the module.allow_web_admin runtime property, which is intended to restrict administrators from managing modules via the web interface, only gates the Legacy UI controller entry point. The REST API endpoint POST /openmrs/ws/rest/v1/module does not check this property, allowing this restriction to be fully bypassed.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2026-40076 has a CVSS score of 8.7 (Critical). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.

Kodem intelligence

Add normalize().startsWith() boundary validation before writing, consistent with the existing pattern in ModuleUtil.expandJar():

File outFile = new File(absPath.toString().replace("/", File.separator));

// ✅ Add this check
if (!outFile.toPath().normalize().startsWith(
        Paths.get(realPath, "WEB-INF").normalize())) {
    throw new UnsupportedOperationException(
        "Zip entry '" + name + "' would be written outside the allowed directory.");
}

Additionally, enforce the module.allow_web_admin restriction consistently across all module upload entry points, including the REST API.

1. What is CVE-2026-40076? CVE-2026-40076 is a critical-severity path traversal vulnerability in org.openmrs.web:openmrs-web (maven), affecting versions <= 2.7.8. No fixed version is listed yet. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-40076? CVE-2026-40076 has a CVSS score of 8.7 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of org.openmrs.web:openmrs-web are affected by CVE-2026-40076? org.openmrs.web:openmrs-web (maven) versions <= 2.7.8 is affected.
4. Is there a fix for CVE-2026-40076? No fixed version is listed for CVE-2026-40076 yet. Monitor the advisory for updates and apply mitigations in the interim.
5. Is CVE-2026-40076 exploitable, and should I be worried? Whether CVE-2026-40076 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-40076 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-40076? No fixed version is listed yet. In the interim: Resolve the canonical path after applying any user-supplied input, and verify it remains within the intended directory before accessing it.