vulnerability / NVI-00008904 / Revision 4
better-auth: OAuth state can be used as a Magic Link to sign in as another user
GitHub lists this reviewed advisory for better-auth. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
9.1 critical
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
0.420%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.36329. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
better-auth
source listed>= 1.4.0-beta.18, < 1.7.7
## Am I affected? You may be affected if you use `better-auth` from `1.4.0-beta.18` through versions before `1.7.7` with the Magic Link plugin and social or Generic OAuth sign-in. You are affected if **all** of these are true: - Magic Link is enabled with default `storeToken: "plain"`, or with `storeToken: "hashed"` and global `verification.storeIdentifier: "hashed"` (including a hashed default). - At least one built-in social provider or Generic OAuth provider is enabled. - OAuth state uses `account.storeStateStrategy: "database"`, the default when a database or secondary storage is configured. Cookie-backed state blocks this path, subject to the OAuth Proxy condition below. With custom hashers, confirm the flows cannot resolve to the same stored identifier. ## Summary Better Auth accepts an OAuth sign-in state value as a Magic Link token. An attacker can start an OAuth sign-in with any email address and use the returned state value to finish a Magic Link sign-in for that address. They never prove that they can read that email. ## Impact An unauthenticated attacker who knows a user's email address can get a normal session for that user, with all of that account's permissio
better-auth
source listedSEMVER: introduced 1.4.0-beta.18; fixed 1.7.7
## Am I affected? You may be affected if you use `better-auth` from `1.4.0-beta.18` through versions before `1.7.7` with the Magic Link plugin and social or Generic OAuth sign-in. You are affected if **all** of these are true: - Magic Link is enabled with default `storeToken: "plain"`, or with `storeToken: "hashed"` and global `verification.storeIdentifier: "hashed"` (including a hashed default). - At least one built-in social provider or Generic OAuth provider is enabled. - OAuth state uses `account.storeStateStrategy: "database"`, the default when a database or secondary storage is configured. Cookie-backed state blocks this path, subject to the OAuth Proxy condition below. With custom hashers, confirm the flows cannot resolve to the same stored identifier. ## Summary Better Auth accepts an OAuth sign-in state value as a Magic Link token. An attacker can start an OAuth sign-in with any email address and use the returned state value to finish a Magic Link sign-in for that address. They never prove that they can read that email. ## Impact An unauthenticated attacker who knows a user's email address can get a normal session for that user, with all of that account's permissio
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
- vendor patch
The original advisory lists fixed boundaries 1.7.7 for better-auth. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-965c-763c-88jm ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-965c-763c-88jm ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-114607 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 4 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.