CVE-2026-67333

better-auth before 1.6.13 Stored XSS via javascript redirect_uri

HIGH
7.2
CVSS Score
Published: August 1, 2026 at 12:22 PM UTC
Updated: September 8, 2026 at 08:49 PM UTC
2 products affected across 1 vendorBetter Auth /oauth ProviderAuth Better Auth

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Severity
HIGH7.2
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.6.13v < 1.7.0
Affected range stops below 1.6.13, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.7.0, so it looks safe — our inference, not a vendor statement
v < 1.6.131.7.0-beta.0 ≤ v < 1.7.0-beta.41.7.0-beta.0
Vendor states this is fixed in 1.6.13 (unaffected)
Vendor states this is fixed in 1.7.0-beta.4 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.2HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-79

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