CVE Catalog

CVE-2026-15144

HighCVSS 7.3
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.25%

17th percentile - higher than 17% of all known CVEs

Summary

In @fastify/rate-limit before version 11.2.0, rate-limit keys are based on the verbatim client IP. An IPv6 client can bypass the limit by rotating addresses or using different representations of the same address. This affects applications using this module to protect endpoints when trustProxy is enabled.

Risk Assessment

An attacker can bypass rate limits, enabling brute-force attacks on authentication, password reset, etc.

Recommendation

Update @fastify/rate-limit to version 11.2.0 or later.

Related vulnerabilities

Original NVD description (English source)

@fastify/rate-limit before 11.2.0 keys rate-limit buckets by the verbatim client IP string returned from request.ip. Because a single IPv6 client can control a large address range (a /64 holds 2^64 distinct addresses) and the same address has multiple valid textual representations, an IPv6 capable client can defeat the rate-limit boundary by rotating addresses or by rewriting the same address in different forms. Applications that use @fastify/rate-limit to protect endpoints such as authentication, password reset, OTP delivery, or expensive API calls can be bypassed by IPv6 clients behind a proxy that surfaces IPv6 to the origin when trustProxy is enabled. The issue is fixed in @fastify/rate-limit 11.2.0, where the default key generator normalizes IPv6 addresses to their canonical form, collapses IPv4 mapped IPv6 to IPv4, and applies a configurable prefix mask (default /64) via a new ipv6Subnet option.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS