{"cve":"CVE-2025-27143","nvd":{"published":"2025-02-24T23:15:11.160","modified":"2026-06-17T09:03:05.560","status":"Analyzed","description":"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 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.","cvss_v4":{"vector":"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","score":6.9},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-601"],"references":["https://github.com/better-auth/better-auth/commit/24659aefc35a536b95ea4e5347e52c8803910153","https://github.com/better-auth/better-auth/commit/b381cac7aafd6aa53ef78b6ab771ebfa24643c80","https://github.com/better-auth/better-auth/releases/tag/v1.1.21","https://github.com/better-auth/better-auth/security/advisories/GHSA-8jhw-6pjj-8723","https://github.com/better-auth/better-auth/security/advisories/GHSA-hjpm-7mrm-26w8"],"products":["better-auth:better_auth"],"source":"nvd","synced_at":"2026-10-19T21:59:48.811064707+00:00"},"epss":{"cve":"CVE-2025-27143","score":0.0035,"percentile":0.287,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-hjpm-7mrm-26w8","url":"https://osv.dev/vulnerability/GHSA-hjpm-7mrm-26w8","summary":"Beter Auth has an Open Redirect via Scheme-Less Callback Parameter","modified":"2026-02-04T02:15:17.765470Z","packages":[{"ecosystem":"npm","name":"better-auth","purl":"pkg:npm/better-auth","ranges":["<1.1.20"],"fixed":["1.1.20"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}