Vulnerability · Published Aug 1, 2026 · Assigned by VulnCheck

CVE-2026-67333better-auth before 1.6.13 Stored XSS via javascript redirect_uri

High 7.2

In plain English

A high-severity cross-site scripting in better-auth from better-auth. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 18% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.2High

Exploit odds (30 days)0.3%top 81.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	better-auth	1.6.13	GHSA-86j7-9j95-vpqj
npm	better-auth	1.7.0-beta.4	GHSA-86j7-9j95-vpqj

Affected products (as reported)

Vendor	Product	Versions
better-auth	better-auth	0 – before 1.6.13
better-auth	better-auth	1.7.0-beta.0 – before 1.7.0-beta.4

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

References

GitHub Security Advisory (GHSA-86j7-9j95-vpqj) vendor-advisory
VulnCheck Advisory: better-auth before 1.6.13 Stored XSS via javascript redirect_uri third-party-advisory