@fastify/rate-limit vulnerable to rate-limit bypass via IPv6 address rotation

{
  "id": "bd42591e4c387839749767f7feb60b538b29210956571d21354d2ac832dd89d8",
  "url": "https://osv.dev/vulnerability/CVE-2026-15144",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "@fastify/rate-limit vulnerable to rate-limit bypass via IPv6 address rotation",
    "summary": "@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.",
    "evidence": "osv:CVE-2026-15144",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-15144",
      "aliases": [
        "CVE-2026-15144",
        "GHSA-grpc-p53c-r64v"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/fastify/fastify-rate-limit",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "92da9644ee157a9abbbaa2925ff86fbd23fe155a"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "11.2.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "cpe": "cpe:2.3:a:fastify:fastify\\/rate-limit:*:*:*:*:*:node.js:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "11.2.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v11.1.0",
            "v11.0.0",
            "v10.3.0",
            "v10.2.2",
            "v10.2.1",
            "v10.2.0",
            "v10.1.1",
            "v10.1.0",
            "v10.0.1",
            "v10.0.0",
            "v9.1.0",
            "v9.0.1",
            "v9.0.0",
            "v8.0.3",
            "v8.1.0",
            "v8.0.2",
            "v8.0.1",
            "v8.0.0",
            "v7.6.0",
            "v7.5.0",
            "v7.4.0",
            "v7.2.0",
            "v7.1.0",
            "v7.0.0",
            "v6.0.1",
            "v6.0.0",
            "v5.8.0",
            "v5.7.2",
            "v5.7.1",
            "v5.7.0",
            "v5.6.2",
            "v5.6.1",
            "v5.6.0",
            "v5.5.0",
            "v5.4.1",
            "v5.4.0",
            "v5.3.0",
            "v5.2.0",
            "v5.1.0",
            "v5.0.1",
            "v5.0.0",
            "v4.1.0",
            "v4.0.3",
            "v4.0.2",
            "v4.0.1",
            "v4.0.0",
            "v3.0.1",
            "v3.0.0",
            "v2.4.0",
            "v2.3.0",
            "v2.2.0",
            "v2.1.1",
            "v2.1.0",
            "v2.0.1",
            "v2.0.0",
            "v1.0.0",
            "v0.3.0",
            "v0.2.0",
            "v0.1.1",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-15144.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.559770223Z",
      "provider": "osv",
      "references": [
        "https://cna.openjsf.org/security-advisories.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/15xxx/CVE-2026-15144.json",
        "https://github.com/fastify/fastify-rate-limit/security/advisories/GHSA-grpc-p53c-r64v",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-15144"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-307",
          "CWE-770"
        ],
        "cna_assigner": "openjs",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/15xxx/CVE-2026-15144.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-15144",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 499512,
  "published_at": "2026-07-29T16:10:24.56+00:00"
}