CVE-2026-45364

Published: Mag 29, 2026 Last Modified: Mag 29, 2026

ExploitDB:

Other exploit source:

Google Dorks:

HIGH 7,3

Source: [email protected]

Attack Vector: network

Attack Complexity: low

Privileges Required: none

User Interaction: none

Scope: unchanged

Confidentiality: low

Integrity: low

Availability: low

Description

AI Translation Available

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.4.17 and 1.5.0-beta.9, Better Auth's HTTP rate limiter keyed each request by the exact textual IP address it received in x-forwarded-for (or the configured IP-bearing header). IPv6 clients controlling a typical /64 allocation could rotate through 2^64 distinct source addresses without exhausting the per-address counter, defeating rate limiting on /sign-in/email, /sign-up/email, /forget-password, and every other path the limiter protects. The same bug allowed a single client to vary the textual encoding of one IPv6 address (uppercase, compression, IPv4-mapped, hex-encoded IPv4-in-IPv6) and produce multiple distinct keys. This vulnerability is fixed in 1.4.17 and 1.5.0-beta.9.