Improper Handling of URL Encoding (Hex Encoding)

Overview @fastify/static is a Plugin for serving static files as fast as possible. Affected versions of this package are vulnerable to Improper Handling of URL Encoding Hex Encoding via the handling of percent-encoded path separators in the fastifyStatic function. This creates a mismatch between...

CVE-2026-6414 @fastify/static vulnerable to route guard bypass via encoded path separators

@fastify/static versions 8.0.0 through 9.1.0 decode percent-encoded path separators %2F before filesystem resolution, while Fastify's router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static. F...

CVE-2026-6414

@fastify/static versions 8.0.0 through 9.1.0 decode percent-encoded path separators %2F before filesystem resolution, while Fastify's router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static. F...

CVE-2026-6414 @fastify/static vulnerable to route guard bypass via encoded path separators

@fastify/static versions 8.0.0 through 9.1.0 decode percent-encoded path separators %2F before filesystem resolution, while Fastify's router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static. F...

CVE-2026-6414

The CVE concerns @fastify/static (versions 8.0.0–9.1.0) where percent-encoded path separators (%2F) are decoded before filesystem resolution, but Fastify’s router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware/guards that protect files served by...

CVE-2026-6414 @fastify/static vulnerable to route guard bypass via encoded path separators

@fastify/static versions 8.0.0 through 9.1.0 decode percent-encoded path separators %2F before filesystem resolution, while Fastify's router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static. F...

Improper Access Control

@fastify/express is vulnerable to Improper Access Control. The vulnerability is due to incorrect path handling in the onRegister function, where middleware paths are duplicated when inherited by child plugins, causing them to not match incoming requests and resulting in bypass of security control...

@cmmn/tools (>=3.0.0-alpha-1, <=3.0.0-alpha-6), mikr0 (0.1.10) potentially affected by CVE-2026-33808 via @fastify/express (>=4.0.1, <=4.0.2)

@fastify/express NPM version =4.0.1, =3.0.0-alpha-1, =3.0.0-alpha-6 - mikr0 0.1.10 Source cves: CVE-2026-33808 Source advisory: OSV:GHSA-6HW5-45GM-FJ88...

GHSA-6HW5-45GM-FJ88 @fastify/express has a middleware authentication bypass via URL normalization gaps (duplicate slashes and semicolons)

Summary @fastify/express v4.0.4 fails to normalize URLs before passing them to Express middleware when Fastify router normalization options are enabled. This allows complete bypass of path-scoped authentication middleware via two vectors: 1. Duplicate slashes //admin/dashboard when...

@fastify/express has a middleware authentication bypass via URL normalization gaps (duplicate slashes and semicolons)

Summary @fastify/express v4.0.4 fails to normalize URLs before passing them to Express middleware when Fastify router normalization options are enabled. This allows complete bypass of path-scoped authentication middleware via two vectors: 1. Duplicate slashes //admin/dashboard when...

EUVD-2026-22881

@fastify/express has a middleware authentication bypass via URL normalization gaps duplicate slashes and semicolons...

@fastify/express's middleware path doubling causes authentication bypass in child plugin scopes

Summary @fastify/express v4.0.4 contains a path handling bug in the onRegister function that causes middleware paths to be doubled when inherited by child plugins. This results in complete bypass of Express middleware security controls for all routes defined within child plugin scopes that share ...

@cmmn/tools (>=3.0.0-alpha-1, <=3.0.0-alpha-6), mikr0 (0.1.10) potentially affected by CVE-2026-33807 +1 more via @fastify/express (>=4.0.1, <=4.0.2)

@fastify/express NPM version =4.0.1, =3.0.0-alpha-1, =3.0.0-alpha-6 - mikr0 0.1.10 Source cves: CVE-2026-33807, CVE-2026-6270 Source advisory: OSV:GHSA-HRWM-HGMJ-7P9C...

EUVD-2026-22880

@fastify/express's middleware path doubling causes authentication bypass in child plugin scopes...

GHSA-HRWM-HGMJ-7P9C @fastify/express's middleware path doubling causes authentication bypass in child plugin scopes

Summary @fastify/express v4.0.4 contains a path handling bug in the onRegister function that causes middleware paths to be doubled when inherited by child plugins. This results in complete bypass of Express middleware security controls for all routes defined within child plugin scopes that share ...

Fastify's connection header abuse enables stripping of proxy-added headers

Summary @fastify/reply-from and @fastify/http-proxy process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers like access control or identification headers from upstream requests by...

EUVD-2026-22877

Fastify's connection header abuse enables stripping of proxy-added headers...

GHSA-GWHP-PF74-VJ37 Fastify's connection header abuse enables stripping of proxy-added headers

Summary @fastify/reply-from and @fastify/http-proxy process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers like access control or identification headers from upstream requests by...

@cedarjs/api-server (>=1.0.0-canary.12281, <=9.0.0-canary.1784), @cedarjs/cli (>=1.0.0-canary.12281, <=9.0.0-canary.1784) +23 more potentially affected by CVE-2026-33805 via @fastify/http-proxy (>=11.1.2, <=11.4.3)

@fastify/http-proxy NPM version =11.1.2, =1.0.0-canary.12281, =1.0.0-canary.12281, =1.0.0-canary.12281, =1.0.0-canary.12281, =1.0.0-canary.12281, =3.0.0-alpha-1, =0.1.0, =1.0.1, =0.0.1, =1.0.0, =1.0.1, =1.4.4, =1.0.50, =0.0.1, =0.1.65 and more Source cves: CVE-2026-33805 Source advisory:...

CVE-2026-6270: Interpretation Conflict

@fastify/middie versions 9.3.1 and earlier do not register inherited middleware directly on child plugin engine instances. When a Fastify application registers authentication middleware in a parent scope and then registers child plugins with @fastify/middie, the child scope does not inherit the...