CVE-2026-40076: OpenMRS Module Upload Vulnerable to Path Traversal (Zip Slip)

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.9%, percentile 59: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 59% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Needs an account (high (admin)). Exposure depends on who can log in.
• Only applies if your dependency tree includes org.openmrs.web:openmrs-web (Maven) <= 2.7.8, no fixed version listed; org.openmrs.web:openmrs-web (Maven) >= 2.8.0, <= 2.8.5, no fixed version listed. Check your lockfile, including transitive dependencies.

What it is

OpenMRS Core is an open source electronic medical record system platform. In versions 2.7.8 and earlier and versions 2.8.0 through 2.8.5, the module upload endpoint at POST /openmrs/ws/rest/v1/module is vulnerable to a Zip Slip path traversal attack. During automatic extraction of uploaded .omod archives in WebModuleUtil.startModule(), ZIP entries under web/module/ are checked only to see whether the full entry path starts with .., and the remaining path is then concatenated into the destination path without normalization or a boundary check. A crafted archive can therefore include entries such as web/module/../../../../malicious.jsp and cause files to be written outside the intended module directory. An authenticated attacker with module upload access can write arbitrary files to locations such as the web application root and achieve remote code execution by uploading a JSP file and then requesting it. The issue is compounded by the fact that the module.allowwebadmin runtime property is enforced in the legacy UI controller but not in the REST API upload path, so deployments relying on that property to block web-based module administration remain exposed through the REST endpoint. This issue has been fixed in versions after 2.7.8 in the 2.7.x line and in version 2.8.6 and later.

From the GitHub advisory

Affected Versions

version ≤ 2.7.8 (latest version at time of disclosure)

https://github.com/openmrs/openmrs-core

Impact

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.

Weakness type: CWE-22.

Product: org.openmrs.web:openmrs-web (Maven) · Assigned by: GitHub_M · Published: 2026-05-06

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: high (admin)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.90% probability of exploitation activity in the next 30 days; percentile 59.

Timeline

• 2026-05-04 — GitHub-reviewed advisory GHSA-78fc-9688-w8xw published (critical)
• 2026-05-06 — CVE record published by GitHub_M
• 2026-05-07 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-78fc-9688-w8xw github.com
2. CVE.org record CVE-2026-40076 cve.org
3. NVD entry CVE-2026-40076 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com

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