VDB-385296 · CVE-2026-67336 · EUVD-2026-51816

better-auth up to 1.6.10 oidcProvider/mcp data authenticity

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.
7.0	$0-$5k	3.25-

Summaryinfo

A vulnerability, which was classified as critical, was found in better-auth up to 1.6.10. Affected is an unknown function of the component oidcProvider/mcp. The manipulation results in data authenticity. This vulnerability is identified as CVE-2026-67336. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in better-auth up to 1.6.10. It has been classified as critical. Affected is some unknown functionality of the component oidcProvider/mcp. The manipulation with an unknown input leads to a data authenticity vulnerability. CWE is classifying the issue as CWE-345. The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

better-auth versions before 1.6.11 contain insecure cryptographic defaults in the oidcProvider and mcp plugins that advertise the none algorithm and accept plain PKCE by default. Attackers can exploit algorithm negotiation to accept unsigned tokens or intercept authorization codes when PKCE plain is used instead of the required S256 method.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-67336 since 07/29/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available.

Upgrading to version 1.6.11 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-51816). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Name

better-auth

Version

Website

Product: https://github.com/better-auth/better-auth/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

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: Data authenticity
CWE: CWE-345
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: better-auth 1.6.11

Timelineinfo

07/29/2026 CVE reserved
08/01/2026 +3 days Advisory disclosed
08/01/2026 +0 days VulDB entry created
08/01/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-67336 (🔒)
GCVE (CVE): GCVE-0-2026-67336
GCVE (VulDB): GCVE-100-385296
EUVD: 🔒

Entryinfo

Created: 08/01/2026 15:27
Updated: 08/01/2026 20:17
Changes: 08/01/2026 15:27 (54), 08/01/2026 20:17 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.