chore(deps): update dev dependency fastify to v5.8.3 [security]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
fastify (source)	5.8.2 → 5.8.3

GitHub Vulnerability Alerts

CVE-2026-3635

Summary

When trustProxy is configured with a restrictive trust function (e.g., a specific IP like trustProxy: '10.0.0.1', a subnet, a hop count, or a custom function), the request.protocol and request.host getters read X-Forwarded-Proto and X-Forwarded-Host headers from any connection — including connections from untrusted IPs. This allows an attacker connecting directly to Fastify (bypassing the proxy) to spoof both the protocol and host seen by the application.

Affected Versions

fastify <= 5.8.2

Impact

Applications using request.protocol or request.host for security decisions (HTTPS enforcement, secure cookie flags, CSRF origin checks, URL construction, host-based routing) are affected when trustProxy is configured with a restrictive trust function.

When trustProxy: true (trust everything), both host and protocol trust all forwarded headers — this is expected behavior. The vulnerability only manifests with restrictive trust configurations.

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Release Notes

fastify/fastify (fastify)

v5.8.3

Compare Source

⚠️ Security Release

This fixes CVE CVE-2026-3635 GHSA-444r-cwp2-x5xf.

What's Changed

• docs(readme): add @​Tony133 to plugin team by @​Tony133 in #​6565
• Updated Plugins-Guide.md; Changed "fastify" to "instance" during plugin registration to showcase that it's added as a child by @​kyrylchenko in #​6566
• test: use fastify.test in test case by @​climba03003 in #​6568
• docs: use fastify.example in documentation by @​climba03003 in #​6567
• docs: add common performance degradation guidance by @​maxpetrusenko in #​6520
• docs(server): fix camelCase anchor links in TOC by @​Deepvamja in #​6530
• ci(link-checker): fix root-relative links resolution by @​barba-rossa in #​6535
• docs: update syntax markdown, absolute paths and links by @​Tony133 in #​6569
• docs: clarify content-type parser/schema mismatch is outside threat model by @​mcollina in #​6537
• docs: fix incorrect code examples in Reply and Request reference by @​mahmoodhamdi in #​6582
• docs: replace redirected npm.im http-errors link by @​mcollina in #​6588
• types: Allow port to be null in request type definition by @​TristanBarlow in #​6589
• docs: update links by @​Tony133 in #​6593
• ci(lock-threads): use shared lock-threads workflow by @​Fdawgs in #​6592

New Contributors

• @​kyrylchenko made their first contribution in #​6566
• @​maxpetrusenko made their first contribution in #​6520
• @​Deepvamja made their first contribution in #​6530
• @​barba-rossa made their first contribution in #​6535
• @​mahmoodhamdi made their first contribution in #​6582
• @​TristanBarlow made their first contribution in #​6589

Full Changelog: fastify/fastify@v5.8.2...v5.8.3

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🎉 This PR is included in version 5.0.19 🎉

The release is available on:

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• GitHub release

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