# CVE-2025-71400 — better-auth passkey

> As of 2026-08-03, CVE-2025-71400 is a HIGH-severity vulnerability in better-auth passkey, CVSS v3.1 7.1, EPSS 0.2% (10.3th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2025-71400 as of 2026-08-03; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-03

## What is CVE-2025-71400?

better-auth passkey versions before 1.4.0 contain an insecure direct object reference vulnerability in the passkey deletion endpoint that allows authenticated users to delete arbitrary passkeys by ID. Attackers with valid sessions can submit crafted requests to the delete-passkey endpoint with enumerated passkey IDs to remove other users' passkeys.

The record classifies CVE-2025-71400 under weakness class [CWE-639](https://intel.threadlinqs.com/cwe/CWE-639). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 64 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.1 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L`)
- **CVSS v4.0 base score:** 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 10.3% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-02, last modified 2026-08-03

## Is CVE-2025-71400 being exploited?

It currently carries a trending score of 32 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **better-auth**: passkey

## How to fix CVE-2025-71400

No vendor patch reference has been recorded for CVE-2025-71400 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2025-71400

No threat campaign in the Threadlinqs corpus currently references CVE-2025-71400, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-08-04.

**Vendor advisory and patch**

- [github.com — vendor advisory](https://github.com/better-auth/better-auth/security/advisories/GHSA-4vcf-q4xf-f48m)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/better-auth-passkey-before-idor-via-delete-passkey)

Canonical: https://intel.threadlinqs.com/cve/CVE-2025-71400
Full detection coverage and IOCs for threats exploiting CVE-2025-71400 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp