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🛡️ CVE-2026-15144 — rate-limit

🟠 CVSS 7.3 — High ✅ No Known Exploit CWE-307 NVD
7.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

@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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity low, availability low.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: Low — limited, and the attacker does not choose what is affected.

Weakness class

CVE-2026-15144 is classified as CWE-307: Improper Restriction of Excessive Authentication Attempts. Repeated login attempts are not limited, leaving credentials open to brute forcing.

Affected software

CVE-2026-15144 is recorded against 1 package.

  • fastify\/rate-limit (fixed in 11.2.0)

Timeline and source

Published on 29 July 2026 and last revised on 5 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

cna.openjsf.org
github.com

Same weakness in other software

These advisories are the same class of weakness (CWE-307: Improper Restriction of Excessive Authentication Attempts) in other software:

Details

Severity HIGH
CVSS Score 7.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CWE CWE-307
Public Exploit ✅ No
Source NVD
Published 2026-07-29
Updated 2026-08-20
Modified 2026-08-05
Fix URL N/A

Affected Packages

Software From version Fixed in
fastify\/rate-limit — 11.2.0

Site Security Check

Is rate-limit part of your stack?

CVE-2026-15144 is rated CVSS 7.3 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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