CriticalCVE-2026-114607

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

Published 22.10.2026Last modified 23.10.2026Sources: OSV, CVE.org, Hersteller

What is affected, what to do

Update better-auth to version 1.7.7.

Affected: Better-auth gte 1.4.0-beta.18, < 1.7.7..*

Not sure whether and how you are affected? Ask a question about this vulnerability

Metrics

9.1

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: Vendor (CNA), CVSS v3

9.1

CVSS v3

Severity Critical on the scale from 0 to 10.

Source: OSV, CVE.org, Hersteller

0.4 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 36.2

Show all metrics

Severity: Critical
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 86.00 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: no public PoC known
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 9.1 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 9.1
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 0.4 %; Low — model estimates < 1% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 36.2; High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: —
Published: 22.10.2026
CISA assessment (SSVC): Exploitation: none known · automatable · Technical impact: total; Source: CISA Vulnrichment, as of 23 October 2026
CWE CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect. Read in glossary: CWE-287

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

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 permissions. They need no access to the mailbox, and they do not need to sign in with the OAuth provider or complete an OAuth callback.

If Magic Link sign-up is enabled and no user has the email address, the attacker can instead create an account that Better Auth wrongly marks as email verified, and is signed in to it. The false verified-email flag can also bypass Better Auth's default unproven-account protections when the mailbox owner later signs in, leaving the attacker's session in that account. Applications that trust verified email addresses or email domains may give this account more access, depending on the application.

Patches

The fix is merged for the planned better-auth 1.7.7 release. That package is not available yet.

Upgrade better-auth and installed Better Auth adapters, plugins, and integrations released alongside it together. Upgrade servers sharing verification storage in the same cutover. Request new Magic Links and restart pending OAuth or SAML sign-ins; links and state created before the upgrade cannot complete. Update custom verification.storeIdentifier.overrides rules to match the magic-link: and auth-state: prefixes. There is no user or account data migration, and public token values and API signatures are unchanged.

Workarounds

Until you upgrade to the fixed release, use one of these mitigations:

Set account.storeStateStrategy to "cookie". If you also use OAuth Proxy, first configure one dedicated OAuth Proxy secret across all participating environments that differs from each environment's global Better Auth secret. Cookie-backed state can expose a separate OAuth Proxy account-takeover path when the proxy shares the global secret and implicit account linking is enabled.
Set the Magic Link plugin option storeToken to "hashed" and leave global verification.storeIdentifier unset or set it to "plain". Global identifier hashing does not prevent this issue when Magic Link tokens are also hashed.
Turn off Magic Link sign-in, or turn off social and Generic OAuth sign-in.

Setting disableSignUp: true on the Magic Link plugin is not enough. It only stops the creation of new verified accounts. It does not stop the takeover of existing accounts.

Source: OSV (Open Source Vulnerabilities), NVD (NIST), GitHub Security Advisories, cvelistv5

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
better-auth	better-auth	`≥ 1.4.0-beta.18, < 1.7.7`	—
npm	better-auth	`>= 1.4.0-beta.18, < 1.7.7` `1.4.0-beta.18`	`1.7.7` `1.7.7`

Vendors and products

Better-auth Better-auth

Weakness classes (CWE)

CWE-287Improper Authentication
Class
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
Entry at MITRE CWE-287

References & sources

github.combetter-auth/better-auth/security/advisories/GHSA-965c-763c-88jmx_refsource_CONFIRM, advisory, web
github.combetter-auth/better-auth/pull/11494x_refsource_MISC, web
github.combetter-auth/better-auth/commit/ac54bfd67821a7607533af2059858b12…x_refsource_MISC, web
github.combetter-auth/better-auth/releases/tag/v1.7.7x_refsource_MISC, web
github.comCVEProject/cvelistV5/tree/main/cves/2026/110xxx/CVE-2026-110862…advisory
NVD (NIST)vuln/detail/CVE-2026-110862advisory
vulncheck.comadvisories/better-auth-1.4.0-beta.18-before-1.7.7-authenticatio…advisory
NVD (NIST)vuln/detail/CVE-2026-114607advisory
github.combetter-auth/better-authpackage

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

23.10.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: none known, automatable: yes

Show the original change

Individual changes of this event as published by NVD
Type	Action	Before	After
SSVC assessment	added	—	{"id":"CVE-2026-114607","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-23T14:55:53.151034Z"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

22.10.2026ReceivedGitHub

CVSS V3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Weakness type: CWE-287

Description added or changed

New references:

Show 8 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Description	added	—	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.
CVSS	added	—	AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness type (CWE)	added	—	CWE-287
Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/114xxx/CVE-2026-114607.json">CVE-2026-114607</a>
Reference	added	—	https://github.com/better-auth/better-auth/commit/ac54bfd67821a7607533af2059858b12bc54e26a
Reference	added	—	https://github.com/better-auth/better-auth/pull/11494
Reference	added	—	https://github.com/better-auth/better-auth/releases/tag/v1.7.7
Reference	added	—	https://github.com/better-auth/better-auth/security/advisories/GHSA-965c-763c-88jm

Source identifier: security-advisories@github.com

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