CVE-2025-71404

better-auth before 1.1.16 Reflected XSS via error parameter

At a glance

Severity: MEDIUM 5.1
EPSS: EPSS 0.52 % · percentile 44 (2026-10-27)
State: PUBLISHED
Published: 2026-08-01
Updated: 2026-08-03
Assigner: VulnCheck
NVD status: Deferred

Description

better-auth versions after v0.0.2 and before 1.1.16 contain a reflected cross-site scripting (XSS) vulnerability on the /api/auth/error page, where the value of the 'error' URL parameter is reflected as HTML without proper neutralization. An attacker who coerces a user into visiting a specially-crafted URL can execute arbitrary JavaScript in the context of the user's browser. The issue is fixed in version 1.1.16.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	MEDIUM 5.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N	VulnCheck
CVSS 4.0	MEDIUM 5.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/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	NVD · disclosure@vulncheck.com (Secondary)

Weaknesses (CWE)

CWE-79

Advisories

GHSA-9x4v-xfq5-m8x5 — Better Auth URL parameter HTML Injection (Reflected Cross-Site scripting)

European references

ENISA EUVD · EUVD-2025-210583
GCVE · GCVE-0-2025-71404

Affected products

Product	Versions
better-auth · better-auth	affected 0 < 1.1.16 ; unaffected 1.1.16

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD