Better Auth vulnerable to unauthorized invitation acceptance via unverified email match in organization plugin

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.7 · CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

EPSS

• CVE-2026-53514: 0.20% estimated exploitation activity in the next 30 days; percentile 10.02 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Am I affected? Users are affected if all of the following are true: - Their application uses better-auth with the organization plugin (import { organization } from "better-auth/plugins/organization"). - Their application enables a sign-up surface that allows arbitrary unverified email registration. Most commonly emailAndPassword: { enabled: true } without requireEmailVerification: true. - Their application has not set requireEmailVerificationOnInvitation: true on the organization() options. - Their application invitation distribution flow allows anyone other than the invited mailbox owner to obtain the invitationId. Examples: admin UI surfacing the link, copy-paste into chat, forwarded email, mail-forwarding rules at the recipient's domain, link previews logging the URL, or a custom sendInvitationEmail integration that sends to a non-owner channel. If their application set emailAndPassword: { enabled: true, requireEmailVerification: true } so unverified rows cannot reach a usable…

Published by the source

7 Jul 2026, 20:54 UTC

Last modified by the source

20 Jul 2026, 19:30 UTC

Source last checked

26 Oct 2026, 12:57 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-fmh4-wcc4-5jm3

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-fmh4-wcc4-5jm3

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# Patch Next advisory brief: CVE-2026-53514

Advisory: Better Auth vulnerable to unauthorized invitation acceptance via unverified email match in organization plugin
IDs: CVE-2026-53514, GHSA-fmh4-wcc4-5jm3
Record: https://patchnext.com/advisories/cve-2026-53514 (revision 2, source checked 26 Oct 2026, 12:57 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: better-auth 1.6.11. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm better-auth: affected < 1.6.11; fixed in 1.6.11

## Suggested inspection (read-only)
- `npm ls better-auth --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on better-auth.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-fmh4-wcc4-5jm3 (OSV record GHSA-fmh4-wcc4-5jm3 lists affected ranges: npm better-auth >=0 <1.6.11 (fixed))
- Verified: https://github.com/advisories/GHSA-fmh4-wcc4-5jm3 (GitHub-reviewed advisory GHSA-fmh4-wcc4-5jm3 lists affected ranges: npm better-auth >=0 <1.6.11)

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