---
id: "CVE-2026-126421"
page: "https://infrastack.ai/live/CVE-2026-126421"
kind: "vulnerability"
aliases: ["CVE-2026-126421"]
title: "OpenEMR: unbounded count parameter lets authenticated users exhaust PHP workers"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["healthcare", "openemr", "package", "php", "self-hosted"]
not_affected_if: ["no-patients-med-users", "openemr-8.5.0-or-later"]
published_at: "2026-11-13T10:17:48+00:00"
first_seen_at: "2026-11-13T10:47:21+00:00"
updated_at: "2026-11-13T10:57:18+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126421", "first_seen_at": "2026-11-13T10:47:21+00:00"}]
exploit_sources: []
---

# OpenEMR: unbounded count parameter lets authenticated users exhaust PHP workers

Link for people: https://infrastack.ai/live/CVE-2026-126421 (this .md is for agents)

OpenEMR before 8.5.0 accepts an unbounded count parameter in print_labels requests to labs_ajax.php. An authenticated user with patients/med access can force huge mPDF and barcode generation and make the application unavailable.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed OpenEMR version against the fixed release `8.5.0`
- Review whether `labs_ajax.php` is reachable by users who hold the patients/med permission

## Fix

- OpenEMR: move to `8.5.0` or later

## Timeline

- 2026-11-13T10:47:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-126421

## Documents

- [advisory] Vendor advisory: github.com https://github.com/openemr/openemr/security/advisories/GHSA-3j3r-w7q7-h9fj
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/openemr-before-8.5.0-denial-of-service-via-labs-ajax-php-label-count

## From the sources

OpenEMR before 8.5.0 contains an uncontrolled resource consumption vulnerability that allows authenticated users with patients/med access to exhaust PHP workers via an unbounded count parameter. Attackers can send print_labels requests to labs_ajax.php with huge counts, forcing mPDF page and barcode generation that makes OpenEMR unavailable.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_