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Response snapshot Oct 27, 2026, 16:01 UTC

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VulnerabilityGHSA-q84f-53jg-9ppm

better-auth: Device login approval does not show the requesting client or permissions

You may be affected if you use `better-auth` from `1.3.8-beta.3` up to, but not including, `1.7.0-rc.3`, and you enable the `deviceAuthorization()` plugin. This range includes all 1.6 releases. You are affected only if all of these are also true:

Published Updated

At a glance

Exploited
Not known
Severity
Not scored yet
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: better-auth: 1.7.0-rc.3. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-q84f-53jg-9ppm (opens a new tab)

What happened

## Am I affected?

You may be affected if you use `better-auth` from `1.3.8-beta.3` up to, but not including, `1.7.0-rc.3`, and you enable the `deviceAuthorization()` plugin. This range includes all 1.6 releases.

You are affected only if all of these are also true:

- An attacker can start a device request: `validateClient` is not configured, or the attacker can use a valid public client. - Before allowing approval, your approval page does not show, from server-checked data, which client is asking and the exact permissions it requests. - Users may approve a code or complete verification link they did not start and cannot compare with a device they have.

Continue reading

- Your application accepts the session token that the device flow returns, for example through the bearer plugin.

You are not affected if you do not enable the opt-in `deviceAuthorization()` plugin.

## Summary

The device authorization plugin lets a user sign in on one device by approving a short code on another. In affected versions, the approval information given to the user leaves out which client asked for access and which permissions it wants. The official approval examples therefore show only a generic request and a code, so users cannot tell their own device from an attacker's request.

## Impact

An attacker who convinces a signed-in user to approve the attacker's code receives a live Better Auth session token for that user. The attacker can then read or change any data the user's account can access. The attack needs the opt-in device flow, a request the attacker creates, and a user who actively approves it; it is not a sign-in bypass without user action.

## Patches

The fix first shipped in `1.7.0-rc.3`. Upgrade to `better-auth@1.7.0` or later. No 1.6 release contains the fix.

After upgrading, `GET /device` returns the requesting `client_id` and `scope` to the signed-in account that owns the request. If you built your own approval page, update it to show that client and those permissions, and keep approval disabled until they load.

## Workarounds

If you cannot upgrade yet, do the following:

- Disable `deviceAuthorization()`, or block untrusted access to `/device/code`. - Configure a strict `validateClient` allowlist. Do not rely on the allowlist alone: it limits who can start the flow, but it does not give users the missing approval information. - Build your own approval endpoint.

It should read the pending request from trusted server-side storage and map the checked client identifier to a trusted display name. Show the exact requested permissions and the user code. Keep approval disabled until this information loads. - Tell users to reject device requests they did not expect. They should approve only when the same code is visible right now on a device they have.

## Technical details

A device starts the flow by calling `/device/code`. The plugin stores the client identifier and any requested scope with the pending request. Before approval, `GET /device` returns only the user code and its status. This is true even for a signed-in session of the user account that owns the request. An approval page built from that response cannot show which client asked for access or which permissions it wants.

After approval, the original device code can be redeemed at `/device/token` for a Better Auth session token.

RFC 8628 describes this remote phishing scenario. It recommends that the server tell users they are authorizing a device and ask them to confirm that the device is in their possession. It also recommends showing device information that helps users detect impersonation. Client allowlisting reduces who can start the flow, but it does not give users the missing approval information.

A valid public client can therefore still be affected when its identifier and requested permissions are not shown.

Affected package ranges reported by GitHub: better-auth: >= 1.3.8-beta.3, < 1.7.0-rc.3

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-q84f-53jg-9ppm (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-q84f-53jg-9ppm, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 27). better-auth: Device login approval does not show the requesting client or permissions. https://kevwire.com/record/GHSA-q84f-53jg-9ppm

MLA

"better-auth: Device login approval does not show the requesting client or permissions." KEVWire, 27 Oct. 2026, kevwire.com/record/GHSA-q84f-53jg-9ppm.

Chicago

KEVWire. "better-auth: Device login approval does not show the requesting client or permissions." Last modified October 27, 2026. https://kevwire.com/record/GHSA-q84f-53jg-9ppm.

Evidence summary (plain text)

better-auth: Device login approval does not show the requesting client or permissions (Oct 27, 2026).
You may be affected if you use `better-auth` from `1.3.8-beta.3` up to, but not including, `1.7.0-rc.3`, and you enable the `deviceAuthorization()` plugin. This range includes all 1.6 releases.

You are affected only if all of these are also true:
Sources:
GitHub-reviewed advisory GHSA-q84f-53jg-9ppm: https://github.com/advisories/GHSA-q84f-53jg-9ppm
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: GHSA-q84f-53jg-9ppm.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 27, 2026, 16:00 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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