CVE-2026-16158 @fastify/reply-from vulnerable to cross-upstream request routing via URL cache key collision

Impact: @fastify/reply-from versions from 8.3.1 up to but not including 12.6.4 build the internal URL cache key by concatenating the destination and source path without a delimiter. Different destination and source pairs can therefore produce the same key while resolving to different upstream URL...

CVE-2026-16158

CVE-2026-16158 affects @fastify/reply-from. The vulnerability stems from how the internal URL cache key is built by concatenating the destination and source paths without a delimiter in versions 8.3.1 up to (but not including) 12.6.4. This can cause key collisions where different upstreams resolv...

CVE-2026-16158

Impact: @fastify/reply-from versions from 8.3.1 up to but not including 12.6.4 build the internal URL cache key by concatenating the destination and source path without a delimiter. Different destination and source pairs can therefore produce the same key while resolving to different upstream URL...

EUVD-2026-45373

Impact: @fastify/reply-from versions from 8.3.1 up to but not including 12.6.4 build the internal URL cache key by concatenating the destination and source path without a delimiter. Different destination and source pairs can therefore produce the same key while resolving to different upstream URL...

PT-2026-60935

Name of the Vulnerable Software and Affected Versions @fastify/reply-from versions 8.3.1 through 12.6.3 Description Internal URL cache keys are constructed by concatenating the destination and source paths without a delimiter. This allows different destination and source pairs to generate identic...