Cyber Resilience

CVE-2025-27143

Medium

Published: 24 February 2025

Published
24 February 2025
Modified
28 February 2025
KEV Added
Patch
CVSS Score v4 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0021 42.6th percentile
Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-27143 is a medium-severity Open Redirect (CWE-601) vulnerability in Better-Auth Better Auth. Its CVSS base score is 6.9 (Medium).

Operationally, ranked at the 42.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Better Auth is an authentication and authorization library for TypeScript. Prior to version 1.1.21, the application is vulnerable to an open redirect due to improper validation of the callbackURL parameter in the email verification endpoint and any other endpoint that…

more

accepts callback url. While the server blocks fully qualified URLs, it incorrectly allows scheme-less URLs. This results in the browser interpreting the URL as a fully qualified URL, leading to unintended redirection. An attacker can exploit this flaw by crafting a malicious verification link and tricking users into clicking it. Upon successful email verification, the user will be automatically redirected to the attacker's website, which can be used for phishing, malware distribution, or stealing sensitive authentication tokens. This CVE is a bypass of the fix for GHSA-8jhw-6pjj-8723/CVE-2024-56734. Version 1.1.21 contains an updated patch.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

better-auth
better auth
≤ 1.1.21

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-601

Security awareness includes verifying URLs and avoiding untrusted redirects that lead to malicious sites.

addresses: CWE-601

Validates redirect targets and URLs to ensure they conform to allowed destinations.

References