# Fastify v6.0.0-alpha.3

- Product: Fastify (https://whatsnew.fyi/product/fastify)
- Vendor: Fastify
- Date: 2026-09-04
- Version: v6.0.0-alpha.3
- Original notes: https://github.com/fastify/fastify/releases/tag/v6.0.0-alpha.3
- Permalink: https://whatsnew.fyi/product/fastify/releases/v6.0.0-alpha.3
- Labels: Pre-release

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **security** — Fix security vulnerability GHSA-9q9j-q6p8-xq58
- **security** — Fix security vulnerability GHSA-hwr6-493r-vm6h
- **security** — Fix security vulnerability GHSA-p68q-wchp-6fh7
- **security** — Fix security vulnerability GHSA-667r-xxjv-c9mm
- **fixed** — callNotFound should run not-found preHandler regardless of registration order

##### ⚠️ Security release

* Fix for https://github.com/fastify/fastify/security/advisories/GHSA-9q9j-q6p8-xq58
* Fix for https://github.com/fastify/fastify/security/advisories/GHSA-hwr6-493r-vm6h
* Fix for https://github.com/fastify/fastify/security/advisories/GHSA-p68q-wchp-6fh7
* Fix for https://github.com/fastify/fastify/security/advisories/GHSA-667r-xxjv-c9mm

##### What's Changed
* docs: fix broken links in Style-Guide.md by @Snehal-Pradhan in https://github.com/fastify/fastify/pull/6966
* test(types): assert LogController.requestCompleted accepts an undefined error by @suzunn in https://github.com/fastify/fastify/pull/6875
* fix: callNotFound should run not-found preHandler regardless of registration order by @mcollina in https://github.com/fastify/fastify/pull/6965
* docs(ecosystem): remove deprecated http-wizard and rename fastify-better-sqlite3 by @ilteoood in https://github.com/fastify/fastify/pull/6972
* chore: npm ignore remaining agent files by @lazerg in https://github.com/fastify/fastify/pull/6996
* docs(contenttypeparser): new strict content-type validation by @bcomnes in https://github.com/fastify/fastify/pull/6925

##### New Contributors
* @Snehal-Pradhan made their first contribution in https://github.com/fastify/fastify/pull/6966
* @suzunn made their first contribution in https://github.com/fastify/fastify/pull/6875
* @bcomnes made their first contribution in https://github.com/fastify/fastify/pull/6925

**Full Changelog**: https://github.com/fastify/fastify/compare/v6.0.0-alpha.2...v6.0.0-alpha.3