CyberSecBulletin
CVE-2026-67327NVD status: Deferred

better-auth: Improper Authentication

Published Updated By the CyberSecBulletin desk

CVE-2026-67327 is a high-severity improper authentication vulnerability in better-auth, with a CVSS 3.1 base score of 8.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 1.6.22, 1.7.0-beta.10 as the first without the flaw, so updating better-auth to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update better-auth to 1.6.22 or 1.7.0-beta.10, whichever matches your release line, or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  4. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
Better-authbetter-auth1.1.3 up to, but not including, 1.6.22; 1.7.0-beta.0 up to, but not including, 1.7.0-beta.101.6.22, 1.7.0-beta.10

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
LowPerformance or availability is reduced.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L. Scored by CNA (vulncheck.com).

Scoring systemScoreSeverityScored by
CVSS 4.08.7HighCNA (vulncheck.com)
CVSS 3.18.3HighCNA (vulncheck.com)

Official description

better-auth versions >= 1.1.3 and < 1.6.22 (and pre-release versions >= 1.7.0-beta.0 and < 1.7.0-beta.10) are vulnerable to account takeover via pre-account hijacking on magic-link and email-OTP sign-in when open email/password registration is enabled. An attacker registers an account with the victim's email address and an attacker-chosen password; the account remains unverified. When the legitimate owner later signs in via the magic-link or email-OTP passwordless flow, the account is marked verified without removing the pre-existing password or revoking existing sessions, so the attacker's password remains valid, granting persistent access to the victim's account. Fixed in 1.6.22 and 1.7.0-beta.10.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

How developers prevent this class of flaw

  • Use an authentication framework or library such as the OWASP ESAPI Authentication feature.

More Improper Authentication vulnerabilities (CWE-287)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in better-auth

All better-auth vulnerabilities

Recent Improper Authentication vulnerabilities

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