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fix(deps): update dependency better-auth to v1.4.2 [security] #2

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fix(deps): update dependency better-auth to v1.4.2 [security] #2

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@renovate renovate bot commented Jul 13, 2025 •
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Note: This PR body was truncated due to platform limits.

This PR contains the following updates:

Package Change Age Confidence
better-auth (source) 1.2.9 -> 1.4.2 age confidence

GitHub Vulnerability Alerts

CVE-2025-53535

Summary

An open redirect has been found in the originCheck middleware function, which affects the following routes: /verify-email, /reset-password/:token, /delete-user/callback, /magic-link/verify, /oauth-proxy-callback.

Details

In the matchesPattern function, url.startsWith( can be deceived with a url that starts with one of the trustedOrigins.

		const matchesPattern = (url: string, pattern: string): boolean => {
			if (url.startsWith("/")) {
				return false;
			}
			if (pattern.includes("*")) {
				return wildcardMatch(pattern)(getHost(url));
			}
			return url.startsWith(pattern);
		};

Open Redirect PoCs

export const auth = betterAuth({
	baseURL: 'http://localhost:3000',
	trustedOrigins: [
		"http://trusted.com"
	],
	emailAndPassword: {
		...
	},
})

/reset-password/:token

image
image 1

/verify-email

image
image

/delete-user/callback

image
image

/magic-link/verify

image
image

/oauth-proxy-callback

image
image

Impact

Untrusted open redirects in various routes.

CVE-2025-61928

Summary

Unauthenticated attackers can create or modify API keys for any user by passing that user's id in the request body to the api/auth/api-key/create route.

Details

The vulnerability exists in the authentication logic at when checking for user authentication then derives the user as session?.user ?? (authRequired ? null : { id: ctx.body.userId }). When no session exists but userId is present in the request body, authRequired becomes false and the user object is set to the attacker-controlled ID. Server-only field validation only executes when authRequired is true (lines 280-295), allowing attackers to set privileged fields. No additional authentication occurs before the database operation, so the malicious payload is accepted. The same pattern exists in the update endpoint.

PoC

curl -X POST http://localhost:3000/api/auth/api-key/create \
   -H 'Content-Type: application/json' \
   -d '{
         "userId": "victim-user-id",
         "name": "zeropath"
       }'

Response contains the new API key whose userId matches the victim, confirming the bypass.

Impact

This is a critical authentication bypass enabling full an unauthenticated attacker can generate an API key for any user and immediately gain complete authenticated access. This allows the attacker to perform any action as the victim user using the api key, potentially compromise the user data and the application depending on the victim's privileges.

This issue was found by ZeroPath.

GHSA-569q-mpph-wgww

Summary

Affected versions of Better Auth allow an external request to configure baseURL when it isn’t defined through any other means. This can be abused to poison the router’s base path, causing all routes to return 404 for all users.

This issue is only exploitable when baseURL is not explicitly configured (e.g., BETTER_AUTH_URL is missing) and the attacker is able to make the very first request to the server after startup. In properly configured environments or typical managed hosting platforms, this fallback behavior cannot be reached.

Details

A combination of X-Forwarded-Host and X-Forwarded-Proto is implicitly trusted. This allows the first request to configure baseURL whenever it is not explicitly configured.

Here's the code that reads the headers:

headers

Here's the call to getBaseURL(), the result is assigned to ctx.baseURL.

write

Here's the router receiving the poisoned basePath:

router

X-Forwarded-Host and X-Forwarded-Proto can be used to modify the pathname of a parsed URL object which forms baseURL. basePath is then derived from the pathname of baseURL. Once the router basePath is poisoned it fails to match & route incoming requests.

Repro

Start a better-auth server with no baseURL configuration.

Send the following request as the first request to the server:

curl -i --location 'https://example.com/api/auth/ok' \
--header 'X-Forwarded-Proto: some:' \
--header 'X-Forwarded-Host: junk'

The better-auth API check endpoint returns 404.

Now send a regular request without the X-Forwarded-Proto and X-Forwarded-Host headers.

curl -i --location 'https://example.com/api/auth/ok'

The better-auth API check endpoint still returns 404.

Example result

attack

We have modified the basePath for the router until the server is restarted. An attacker can repeatedly send these attack requests aiming to persistently exploit the vulnerability.

Release Notes

better-auth/better-auth (better-auth)

v1.4.2

Compare Source

   🚀 Features
   🐞 Bug Fixes
    View changes on GitHub

v1.4.1

Compare Source

   🚀 Features
   🐞 Bug Fixes
    View changes on GitHub

v1.4.0

Compare Source

   🚀 Features
   🐞 Bug Fixes

Configuration

📅 Schedule: Branch creation - "" (UTC), Automerge - At any time (no schedule defined).

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about these updates again.

  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

@renovate renovate bot force-pushed the renovate/npm-better-auth-vulnerability branch from b35ab4d to 71e0586 Compare October 10, 2025 03:57
@renovate renovate bot changed the title fix(deps): update dependency better-auth to v1.2.10 [security] fix(deps): update dependency better-auth to v1.3.26 [security] Oct 10, 2025
@renovate renovate bot force-pushed the renovate/npm-better-auth-vulnerability branch 2 times, most recently from 1a2569c to 9e34c86 Compare November 19, 2025 16:10
@renovate renovate bot force-pushed the renovate/npm-better-auth-vulnerability branch from 9e34c86 to 3e01dfb Compare December 2, 2025 23:56
@renovate renovate bot changed the title fix(deps): update dependency better-auth to v1.3.26 [security] fix(deps): update dependency better-auth to v1.4.2 [security] Dec 2, 2025
@renovate renovate bot force-pushed the renovate/npm-better-auth-vulnerability branch from 3e01dfb to d4a8496 Compare December 4, 2025 19:10
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