CVE-2025-71404Network attack vectorHinoki check available

Browser script execution via unescaped error parameter

Published Aug 1, 2026 · Updated Aug 1, 2026

Reflected XSS in Better Auth before 1.1.16 allows remote attackers to execute JavaScript through a crafted error URL. The /api/auth/error route inserts the error query value into the errorCode span of an HTML template without encoding metacharacters. Exploitation requires a victim to open the attacker-controlled URL; execution can read or modify data available to scripts in that origin.

CVSS severity5.1
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Reflected XSS in Better Auth before 1.1.16 allows remote attackers to execute JavaScript through a crafted error URL. The /api/auth/error route inserts the error query value into the errorCode span of an HTML template without encoding metacharacters. Exploitation requires a victim to open the attacker-controlled URL; execution can read or modify data available to scripts in that origin.

The record

CVE
CVE-2025-71404
Published
Aug 1, 2026
Updated
Aug 1, 2026
Vendor
Better Auth
Product
Better Auth
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2026Record 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.

  1. Affected versionversion=0 <1.1.16

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Better Auth · Better Authversion=0 <1.1.16

Published CVSS scores

5.1Better Auth GitHub Security AdvisoryCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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