fastify fastify-rate-limit up to 11.1.9 Key Generator privileges management

Summaryinfo

A vulnerability categorized as critical has been discovered in fastify fastify-rate-limit up to 11.1.9. This affects an unknown part of the component Key Generator. The manipulation results in privileges management. This vulnerability is known as CVE-2026-15144. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability classified as critical has been found in fastify fastify-rate-limit up to 11.1.9. Affected is an unknown functionality of the component Key Generator. The manipulation with an unknown input leads to a privileges management vulnerability. CWE is classifying the issue as CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. This is going to have an impact on integrity, and availability. CVE summarizes:

@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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-15144 since 07/08/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1068 by the MITRE ATT&CK project.

Upgrading to version 11.2.0 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• fastify

Name

• fastify-rate-limit

Version

• 11.1.0
• 11.1.1
• 11.1.2
• 11.1.3
• 11.1.4
• 11.1.5
• 11.1.6
• 11.1.7
• 11.1.8
• 11.1.9

Website

• Product: https://github.com/fastify/fastify-rate-limit/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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