User redirection via scheme-less callback URL
Published Feb 24, 2025 · Updated Feb 25, 2025
Open redirect in Better Auth before 1.1.20 allows remote attackers to redirect users after email verification via a crafted callback URL. The origin-check middleware treats a callback beginning with a slash as local without rejecting a second slash, so browsers resolve it as an external host. Exploitation requires a user to follow the crafted verification link and complete verification, exposing that user to phishing or token theft.
Summary
What happened
Open redirect in Better Auth before 1.1.20 allows remote attackers to redirect users after email verification via a crafted callback URL. The origin-check middleware treats a callback beginning with a slash as local without rejecting a second slash, so browsers resolve it as an external host. Exploitation requires a user to follow the crafted verification link and complete verification, exposing that user to phishing or token theft.
The record
- CVE
- CVE-2025-27143
- Published
- Feb 24, 2025
- Updated
- Feb 25, 2025
- Vendor
- Better Auth
- Product
- Better Auth
- Classifications
- CWE-601, T1598.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 24, 2025CVE publishedPublication date reported by the CVE source.
- Feb 25, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.1.20
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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