CVE-2026-67333High· 7.2▾ Twilight

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)

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score40/ 100 · Moderate

impact 39.6 · likelihood 0 · exploitation 0

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Proof of concept

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Published

Aug 1, 2026

Updated

Sep 8, 2026

CVSS

7.2

Vendor

—

Product

—

CWE

CWE-79

Depth score

40 · Moderate

EPSS

0.16% · p5

Platforms

—

Source

NVD

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

EPSS history

Exploit-prediction probability, daily snapshots since Aug 2.

0.2% → 0.2%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

3 events · 38 days

Aug 1, 2026Published
Disclosed via NVD
Aug 2, 2026EPSS first tracked
0.2%
Sep 8, 2026Record revised
Last analysed / modified upstream

CWE-79 #nvd

Full technical detail▾

Overview

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.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

References

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#nvd

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