{"action":"Upgrade fastify to 5.12.2 or later.","affected":[{"fixed":"5.12.2","introduced":"0"}],"component":"fastify","cve_ids":["CVE-2026-84428"],"ecosystem":"npm","epss":0.00524,"exploited":false,"fixed_versions":["5.12.2"],"ghsa_id":"GHSA-9q9j-q6p8-xq58","id":"tcs_01M5KFGMN08ANQ4VYM4JJAKSEH","modified_at":"2026-10-01T00:00:05.759936763Z","published_at":"2026-09-30T23:44:27Z","references":["https://osv.dev/vulnerability/GHSA-9q9j-q6p8-xq58","https://github.com/fastify/fastify/security/advisories/GHSA-9q9j-q6p8-xq58","https://nvd.nist.gov/vuln/detail/CVE-2026-84428","https://github.com/fastify/fastify/commit/179619c8e99d54924309b9933402151ef9af37e0","https://cna.openjsf.org/security-advisories.html","https://github.com/fastify/fastify","https://github.com/fastify/fastify/releases/tag/v5.12.2"],"severity":{"label":"high","score":7.5},"sources":[{"source":"osv","source_id":"GHSA-9q9j-q6p8-xq58","url":"https://osv.dev/vulnerability/GHSA-9q9j-q6p8-xq58"}],"summary":"fastify vulnerable to header validation bypass via incomplete schema case normalization"}