VDB-436860 · CVE-2026-126436 · GCVE-0-2026-126436

OpenEMR up to 8.4.x OAuth2 Grant Type Enforcement grant_type authorization

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.8	$0-$5k	0.00+

Summaryinfo

A vulnerability was found in OpenEMR up to 8.4.x and classified as problematic. The affected element is an unknown function of the component OAuth2 Grant Type Enforcement. The manipulation of the argument grant_type results in authorization. This vulnerability is known as CVE-2026-126436. It is possible to launch the attack remotely. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in OpenEMR up to 8.4.x. Affected is an unknown code of the component OAuth2 Grant Type Enforcement. The manipulation of the argument grant_type with an unknown input leads to a authorization vulnerability. CWE is classifying the issue as CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. This is going to have an impact on confidentiality. CVE summarizes:

OpenEMR before 8.5.0 contains an authorization bypass vulnerability that allows OAuth2 clients to use unregistered grant types because oauth_clients.grant_types is never enforced. Attackers can request tokens with grant_type=password to bypass the user consent screen, and disabled clients can redeem authorization codes using JWT client assertions.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-126436 since 11/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available.

Upgrading to version 8.5.0 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Business Process Management Software

Name

OpenEMR

Version

License

open-source

Website

Product: https://github.com/openemr/openemr/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.8

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (VulnCheck): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authorization
CWE: CWE-639 / CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: OpenEMR 8.5.0

Timelineinfo

11/10/2026 CVE reserved
11/13/2026 +3 days Advisory disclosed
11/13/2026 +0 days VulDB entry created
11/13/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CNA: VulnCheck
CVE: CVE-2026-126436 (🔒)

GCVE (CVE): GCVE-0-2026-126436
GCVE (VulDB): GCVE-100-436860

Entryinfo

Created: 11/13/2026 11:47
Changes: 11/13/2026 11:47 (77)
Complete: 🔍
Cache ID: 216::103