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Better Auth allows bypassing the trustedOrigins Protection which leads to ATO

High severity GitHub Reviewed Published Feb 24, 2025 in better-auth/better-auth • Updated Dec 9, 2025

Package

npm better-auth (npm)

Affected versions

<= 1.1.20

Patched versions

1.1.21

Description

Summary

A bypass was discovered in the trustedOrigins validation logic—affecting both absolute URL entries and wildcard domain patterns. This flaw allows an attacker to construct a malicious callbackURL that passes origin checks and triggers an open redirect.

Because redirect endpoints include sensitive tokens (such as password-reset tokens), this vulnerability can enable one-click account takeover if a victim clicks a crafted link.

References

@Bekacru Bekacru published to better-auth/better-auth Feb 24, 2025
Published to the GitHub Advisory Database Feb 24, 2025
Reviewed Feb 24, 2025
Last updated Dec 9, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N

EPSS score

Weaknesses

URL Redirection to Untrusted Site ('Open Redirect')

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. Learn more on MITRE.

CVE ID

No known CVE

GHSA ID

GHSA-vp58-j275-797x

Source code

Credits

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