CVE-2026-67333
Received Received - Intake

Open Redirect in better-auth OAuth Provider

Publication date: 2026-08-01

Last updated on: 2026-08-01

Assigner: VulnCheck

Description
better-auth before 1.6.13 (and pre-release builds 1.7.0-beta.0 through 1.7.0-beta.3) fail to validate the scheme of redirect_uris registered via the deprecated oidc-provider plugin and the mcp plugin (which wraps the same provider). An attacker can register an OAuth client with a javascript: redirect_uri, which the authorization server later returns unchanged in the consent response. If the deployment's consent page navigates the browser to the returned redirectURI (e.g. assigning it to window.location.href), the attacker's JavaScript executes in the authorization-server origin, exposing the victim's session and enabling account takeover.

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Meta Information

Published
2026-08-01
Last Modified
2026-08-01
Generated
2026-08-01
AI Q&A
2026-08-01
EPSS Evaluated
N/A
NVD
CVE-2026-67333
EUVD
EUVD-2026-51810

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
better-auth better-auth to 1.7.0-beta.3 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

The vulnerability in better-auth before 1.6.13 and pre-release builds 1.7.0-beta.0 through 1.7.0-beta.3 involves improper validation of redirect_uris registered via the oidc-provider and mcp plugins. An attacker can register an OAuth client with a javascript: redirect_uri, which the authorization server returns unchanged in the consent response. If the consent page navigates to this URI, the attacker's JavaScript executes in the authorization server's origin, exposing the victim's session and enabling account takeover.

Impact Analysis

This vulnerability allows an attacker to execute arbitrary JavaScript in the context of the authorization server, potentially stealing session tokens, performing actions on behalf of the victim, or taking over their account. Users of applications using affected versions of better-auth could have their accounts compromised if they authorize an attacker-controlled OAuth client.

Mitigation Strategies

Upgrade better-auth to version 1.6.13 or later to address the redirect_uri validation issue. Remove or disable the deprecated oidc-provider and mcp plugins if they are not required.

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