EUVD-2026-40947

@fastify/middie versions 9.1.0 through 9.3.2 fail to guard the URL normalization step used by the standalone engine when incoming request paths contain malformed percent-encoded sequences. Inputs such as an incomplete percent escape or a truncated multibyte sequence cause the underlying decoder t...

CVE-2026-14198 @fastify/middie vulnerable to authorization bypass via encoded slash in path parameter values

@fastify/middie versions 9.1.0 through 9.3.2 decode the encoded slash %2F inside path parameter values before matching middleware paths, while Fastify's underlying router preserves the encoding during route lookup. The two layers disagree on the canonical request path, so the middleware fails to...

@arenahito/droid-webscr (>=0.2.1, <=0.6.1), @cappa/cli (>=0.4.4, <=0.10.4) +2 more potentially affected by CVE-2026-14198 via @fastify/middie (>=9.1.0, <=9.3.2)

@fastify/middie NPM version =9.1.0, =0.2.1, =0.4.4, =0.2.8, =1.0.0-alpha.23, =1.0.0-alpha.28 Source cves: CVE-2026-14198 Source advisory: MEND:CVE-2026-14198...

CVE-2026-14198

@fastify/middie versions 9.1.0 through 9.3.2 decode the encoded slash %2F inside path parameter values before matching middleware paths, while Fastify's underlying router preserves the encoding during route lookup. The two layers disagree on the canonical request path, so the middleware fails to...

CVE-2026-14198

The CVE-2026-14198 entry concerns @fastify/middie versions 9.1.0–9.3.2, where encoded slashes (%2F) in path parameter values are decoded by middie but not by Fastify’s router during route lookup. This mismatch lets a crafted URL bypass middleware-based security (authentication/authorization/rate ...

CVE-2026-14198

@fastify/middie versions 9.1.0 through 9.3.2 decode the encoded slash %2F inside path parameter values before matching middleware paths, while Fastify's underlying router preserves the encoding during route lookup. The two layers disagree on the canonical request path, so the middleware fails to...

CVE-2026-14198 @fastify/middie vulnerable to authorization bypass via encoded slash in path parameter values

@fastify/middie versions 9.1.0 through 9.3.2 decode the encoded slash %2F inside path parameter values before matching middleware paths, while Fastify's underlying router preserves the encoding during route lookup. The two layers disagree on the canonical request path, so the middleware fails to...

CVE-2026-14198 @fastify/middie vulnerable to authorization bypass via encoded slash in path parameter values

@fastify/middie versions 9.1.0 through 9.3.2 decode the encoded slash %2F inside path parameter values before matching middleware paths, while Fastify's underlying router preserves the encoding during route lookup. The two layers disagree on the canonical request path, so the middleware fails to...

EUVD-2026-40946

@fastify/middie versions 9.1.0 through 9.3.2 decode the encoded slash %2F inside path parameter values before matching middleware paths, while Fastify's underlying router preserves the encoding during route lookup. The two layers disagree on the canonical request path, so the middleware fails to...

CVE-2026-14198: Interpretation Conflict

@fastify/middie versions 9.1.0 through 9.3.2 decode the encoded slash %2F inside path parameter values before matching middleware paths, while Fastify's underlying router preserves the encoding during route lookup. The two layers disagree on the canonical request path, so the middleware fails to...

CVE-2026-14181: Uncaught Exception

@fastify/middie versions 9.1.0 through 9.3.2 fail to guard the URL normalization step used by the standalone engine when incoming request paths contain malformed percent-encoded sequences. Inputs such as an incomplete percent escape or a truncated multibyte sequence cause the underlying decoder t...

PT-2026-54638

Name of the Vulnerable Software and Affected Versions @fastify/middie versions 9.1.0 through 9.3.2 Description An issue exists in the standalone engine's URL normalization and decoding process where malformed percent-encoded sequences in incoming request paths are not properly guarded...

Fastify Framework Security Bypass

The vulnerability of the Fastify framework, a Node.js software platform, is related to improper validation of the specified data type during input processing. Exploiting this vulnerability allows an attacker to bypass existing security measures remotely...

PT-2026-54639

Name of the Vulnerable Software and Affected Versions @fastify/middie versions 9.1.0 through 9.3.2 Description An authorization bypass occurs because the software decodes the encoded slash %2F within path parameter values before matching middleware paths, whereas the underlying router preserves...

@bedrock/express (8.6.5), @cmmn/tools (>=3.0.0-alpha-1, <=3.0.0-alpha-6) +1 more potentially affected by CVE-2026-6556 via @fastify/express (>=4.0.1, <=4.0.5)

@fastify/express NPM version =4.0.1, =3.0.0-alpha-1, =3.0.0-alpha-6 - mikr0 0.1.10 Source cves: CVE-2026-6556 Source advisory: SNYK:JS-FASTIFYEXPRESS-17744444...

Incorrect Behavior Order

Overview @fastify/express is an Express compatibility layer for Fastify Affected versions of this package are vulnerable to Incorrect Behavior Order due to incorrect mount path prefix rewriting in the use middleware handling. An attacker can reach protected routes without the intended middleware ...

CVE-2026-6556

@fastify/express versions 4.0.6 and earlier only rewrite the plugin prefix for middleware mount paths when the path argument is a string. Non-string mount paths arrays of paths and regular expressions are left unprefixed inside prefixed plugin scopes, so middleware registered with those forms doe...

CVE-2026-6556 @fastify/express vulnerable to middleware bypass via non-string mount paths in prefixed plugins

@fastify/express versions 4.0.6 and earlier only rewrite the plugin prefix for middleware mount paths when the path argument is a string. Non-string mount paths arrays of paths and regular expressions are left unprefixed inside prefixed plugin scopes, so middleware registered with those forms doe...

CVE-2026-6556

The CVE concerns @fastify/express 4.0.6 and earlier, where non-string mount paths (arrays/regex) are not prefixed inside prefixed plugin scopes. This causes middleware registered with those forms to not match the actual prefixed request path, potentially bypassing path-scoped security middleware ...

CVE-2026-6556 @fastify/express vulnerable to middleware bypass via non-string mount paths in prefixed plugins

@fastify/express versions 4.0.6 and earlier only rewrite the plugin prefix for middleware mount paths when the path argument is a string. Non-string mount paths arrays of paths and regular expressions are left unprefixed inside prefixed plugin scopes, so middleware registered with those forms doe...