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@fastify/accepts-serializer vulnerable to Denial of Service via Unbounded Accept Header Cache Growth

Type: advisorySources: OSV

@fastify/accepts-serializer cached serializer-selection results keyed by the request Accept header without a size limit or eviction policy. A remote unauthenticated client could send many distinct but matching Accept header variants to make the cache grow unbounded, eventually exhausting the Node.js heap and crashing the process. Versions <= 6.0.3 are affected. Update to 6.0.4 or later, which bounds the cache via an LRU with a default size of 100 entries, configurable through the new cacheSize plugin option.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-7768
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 07:56 UTC · Revision 1

Source evidence

@fastify/accepts-serializer vulnerable to Denial of Service via Unbounded Accept Header Cache Growth

core-osv · Original source

Published 4 May 2026, 19:14 UTC

@fastify/accepts-serializer cached serializer-selection results keyed by the request Accept header without a size limit or eviction policy. A remote unauthenticated client could send many distinct but matching Accept header variants to make the cache grow unbounded, eventually exhausting the Node.js heap and crashing the process. Versions <= 6.0.3 are affected. Update to 6.0.4 or later, which bounds the cache via an LRU with a default size of 100 entries, configurable through the new cacheSize plugin option.

osv:CVE-2026-7768
Complete source record
{
  "id": "b44abd280a23027c360d0ad03566c1daa16f57459ecc0a283cb11e0044b96217",
  "url": "https://osv.dev/vulnerability/CVE-2026-7768",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "@fastify/accepts-serializer vulnerable to Denial of Service via Unbounded Accept Header Cache Growth",
    "summary": "@fastify/accepts-serializer cached serializer-selection results keyed by the request Accept header without a size limit or eviction policy. A remote unauthenticated client could send many distinct but matching Accept header variants to make the cache grow unbounded, eventually exhausting the Node.js heap and crashing the process. Versions <= 6.0.3 are affected. Update to 6.0.4 or later, which bounds the cache via an LRU with a default size of 100 entries, configurable through the new cacheSize plugin option.",
    "evidence": "osv:CVE-2026-7768",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-7768",
      "aliases": [
        "CVE-2026-7768",
        "GHSA-qxhc-wx3p-2wmg"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/fastify/fastify-accepts-serializer",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3a45060282c8a1bc935cc5db2e1372a72b1d7428"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "6.0.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "cpe": "cpe:2.3:a:fastify:fastify\\/accepts-serializer:*:*:*:*:*:node.js:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "6.0.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v6.0.3",
            "v6.0.2",
            "v6.0.1",
            "v6.0.0",
            "v5.3.0",
            "v5.2.0",
            "v5.1.0",
            "v5.0.0",
            "v4.0.1",
            "v4.0.0",
            "v3.2.0",
            "v3.1.0",
            "v3.0.1",
            "v2.0.1",
            "v3.0.0",
            "v2.0.0",
            "v1.0.2",
            "v1.0.1",
            "v1.0.0",
            "v0.2.1",
            "v0.2.0",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-7768.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.804166851Z",
      "provider": "osv",
      "references": [
        "https://cna.openjsf.org/security-advisories.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/7xxx/CVE-2026-7768.json",
        "https://github.com/fastify/fastify-accepts-serializer/security/advisories/GHSA-qxhc-wx3p-2wmg",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-7768"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-770"
        ],
        "cna_assigner": "openjs",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/7xxx/CVE-2026-7768.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-7768",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 501010,
  "published_at": "2026-05-04T19:14:36.828+00:00"
}