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Fencer Vulns
critical 9.1

CVE-2026-114607 json

better-auth: OAuth state can be used as a Magic Link to sign in as another user

published 2026-10-22 17 d ago modified 2026-10-23 16 d ago also EUVD-2026-108256

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

Better Auth is an authentication and authorization library for TypeScript. From 1.4.0-beta.18 until 1.7.7, deployments that enable Magic Link with storeToken set to plain, or with storeToken set to hashed and the global verification.storeIdentifier setting also set to hashed, enable a built-in social or Generic OAuth provider, and use account.storeStateStrategy set to database can accept an OAuth sign-in state value as a Magic Link token. These settings can cause Magic Link verification records and OAuth state to resolve to the same stored identifier, allowing an unauthenticated attacker to start OAuth sign-in for a known email address and redeem the returned state through Magic Link without controlling the mailbox or completing the provider callback. The attacker can obtain a normal session for an existing user, or create an account incorrectly marked as email verified when sign-up is enabled. This issue is fixed in version 1.7.7.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
16 d ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

  • better-auth better-auth

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.