{"action":"Upgrade fastify to 5.8.3 or later.","affected":[{"fixed":"5.8.3","introduced":"0"}],"component":"fastify","cve_ids":["CVE-2026-3635"],"ecosystem":"npm","epss":0.00161,"exploited":false,"fixed_versions":["5.8.3"],"ghsa_id":"GHSA-444r-cwp2-x5xf","id":"tcs_01M5KEZ3AK4GRD4ED291752WT5","modified_at":"2026-03-25T19:56:21.108110Z","published_at":"2026-03-25T19:32:28Z","references":["https://osv.dev/vulnerability/GHSA-444r-cwp2-x5xf","https://github.com/fastify/fastify/security/advisories/GHSA-444r-cwp2-x5xf","https://nvd.nist.gov/vuln/detail/CVE-2026-3635","https://cna.openjsf.org/security-advisories.html","https://github.com/fastify/fastify","https://github.com/fastify/fastify/releases/tag/v5.8.3","https://www.cve.org/CVERecord?id=CVE-2026-3635"],"severity":{"label":"medium","score":6.1},"sources":[{"source":"osv","source_id":"GHSA-444r-cwp2-x5xf","url":"https://osv.dev/vulnerability/GHSA-444r-cwp2-x5xf"}],"summary":"fastify: request.protocol and request.host Spoofable via X-Forwarded-Proto/Host from Untrusted Connections"}