{"id":"GHSA-mrq3-vjjr-p77c","summary":"Fastify Vulnerable to DoS via Unbounded Memory Allocation in sendWebStream","details":"### Impact\nA Denial of Service vulnerability in Fastify’s Web Streams response handling can allow a remote client to exhaust server memory. Applications that return a `ReadableStream` (or `Response` with a Web Stream body) via `reply.send()` are impacted. A slow or non-reading client can trigger unbounded buffering when backpressure is ignored, leading to process crashes or severe degradation.\n\n### Patches\nThe issue is fixed in Fastify 5.7.3. Users should upgrade to 5.7.3 or later.\n\n### Workarounds\nAvoid sending Web Streams from Fastify responses (e.g., `ReadableStream` or `Response` bodies). Use Node.js streams (`stream.Readable`) or buffered payloads instead until the project can upgrade.\n\n### References\n- https://hackerone.com/reports/3524779","aliases":["CVE-2026-25224"],"modified":"2026-02-04T18:08:54.461651Z","published":"2026-02-02T22:25:05Z","database_specific":{"nvd_published_at":"2026-02-03T22:16:31Z","cwe_ids":["CWE-770"],"severity":"LOW","github_reviewed":true,"github_reviewed_at":"2026-02-02T22:25:05Z"},"references":[{"type":"WEB","url":"https://github.com/fastify/fastify/security/advisories/GHSA-mrq3-vjjr-p77c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-25224"},{"type":"WEB","url":"https://github.com/fastify/fastify/commit/eb11156396f6a5fedaceed0140aed2b7f026be37"},{"type":"WEB","url":"https://hackerone.com/reports/3524779"},{"type":"PACKAGE","url":"https://github.com/fastify/fastify"}],"affected":[{"package":{"name":"fastify","ecosystem":"npm","purl":"pkg:npm/fastify"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.7.3"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-mrq3-vjjr-p77c/GHSA-mrq3-vjjr-p77c.json","last_known_affected_version_range":"\u003c= 5.7.2"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}