CVE-2026-114607: better-auth: OAuth state can be used as a Magic Link to sign in as another user

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.4%, percentile 36: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 36% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes better-auth (npm) >= 1.4.0-beta.18, < 1.7.7, fixed in 1.7.7. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

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.

Weakness type: CWE-287.

Product: better-auth (npm) · Assigned by: GitHub_M · Published: 2026-10-22

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-11-04): 0.42% probability of exploitation activity in the next 30 days; percentile 36.

Timeline

• 2026-10-22 — CVE record published by GitHub_M
• 2026-10-23 — CVE record last updated
• 2026-10-27 — GitHub-reviewed advisory GHSA-965c-763c-88jm published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-965c-763c-88jm github.com
2. CVE.org record CVE-2026-114607 cve.org
3. NVD entry CVE-2026-114607 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com

Critical npm advisories · Today’s Security Digest