{"id":"CVE-2026-7768","aliases":["EUVD-2026-27131","GHSA-qxhc-wx3p-2wmg"],"status":"published","title":"@fastify/accepts-serializer vulnerable to Denial of Service via Unbounded Accept Header Cache Growth","description":"@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 \u003c= 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.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00284,"percentile":0.21199,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-770"],"published":"2026-05-04T19:14:36Z","modified":"2026-11-11T23:10:00Z","fixes":[{"ecosystem":"npm","package":"@fastify/accepts-serializer","fixed_in":["6.0.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@fastify/accepts-serializer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.0.3"},{"fixed":"6.0.4"}]}]},{"source":"osv","ecosystem":"npm","package":"@fastify/accepts-serializer","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"6.0.4"}]}]}],"products":[{"vendor":"@fastify/accepts-serializer","product":"@fastify/accepts-serializer"},{"vendor":"fastify","product":"fastify\\/accepts-serializer"}],"references":[{"url":"https://cna.openjsf.org/security-advisories.html","tags":["Vendor Advisory","advisory","web"]},{"url":"https://github.com/fastify/fastify-accepts-serializer/security/advisories/GHSA-qxhc-wx3p-2wmg","tags":["Vendor Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-7768","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-qxhc-wx3p-2wmg"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/7xxx/CVE-2026-7768.json","tags":["advisory"]},{"url":"https://github.com/fastify/fastify-accepts-serializer","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-7768","title":"@fastify/accepts-serializer vulnerable to Denial of Service via Unbounded Accept Header Cache Growth","description":"@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 \u003c= 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.","status":"published","published":"2026-05-04T19:14:36.828Z","modified":"2026-05-04T19:50:16.465Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:20:05.830416Z"}],"euvd":[{"id":"EUVD-2026-27131","description":"@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 \u003c= 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.","status":"published","published":"2026-05-04T19:14:36Z","modified":"2026-05-04T19:50:16Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T19:05:17.549765Z"}],"ghsa":[{"id":"GHSA-qxhc-wx3p-2wmg","title":"@fastify/accepts-serializer Vulnerable to Denial of Service via Unbounded Accept Header Cache Growth","description":"### Impact\n\n`@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. Under sustained load, this can exhaust the Node.js heap and crash the process.\n\n### Patches\n\nUpdate to `@fastify/accepts-serializer \u003e= 6.0.4`. The cache is now bounded by an LRU with a default size of 100 entries, configurable via the new `cacheSize` plugin option.\n\n### Workarounds\n\nNone. Upgrade is required.","status":"published","published":"2026-05-08T17:13:38Z","modified":"2026-05-08T17:13:38Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:40:04.762828Z"}],"nvd":[{"id":"CVE-2026-7768","description":"@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 \u003c= 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.","status":"published","published":"2026-05-04T20:16:21.107Z","modified":"2026-11-11T23:10:00.263Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-770"],"updated_at":"2026-11-12T01:26:59.692044Z"}],"osv":[{"id":"CVE-2026-7768","title":"@fastify/accepts-serializer vulnerable to Denial of Service via Unbounded Accept Header Cache Growth","description":"@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 \u003c= 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.","status":"published","published":"2026-05-04T19:14:36.828Z","modified":"2026-10-28T02:30:33.804166851Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:45:17.44708Z"},{"id":"GHSA-qxhc-wx3p-2wmg","title":"@fastify/accepts-serializer Vulnerable to Denial of Service via Unbounded Accept Header Cache Growth","description":"### Impact\n\n`@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. Under sustained load, this can exhaust the Node.js heap and crash the process.\n\n### Patches\n\nUpdate to `@fastify/accepts-serializer \u003e= 6.0.4`. The cache is now bounded by an LRU with a default size of 100 entries, configurable via the new `cacheSize` plugin option.\n\n### Workarounds\n\nNone. Upgrade is required.","status":"published","published":"2026-05-08T17:13:38Z","modified":"2026-05-08T17:41:26.391342Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:46:55.122811Z"}]}}