Skip to main content
← All vulnerabilities
CVE-2026-16158

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

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 12.6.4
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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 URLs. When getUpstream selects an upstream from request data, a URL cached for one upstream can be reused for a request intended for another upstream, causing cross-upstream data access and modification. The default configuration is affected. Setting disableCache to true prevents the behavior. Patches: upgrade to @fastify/reply-from 12.6.4. Workarounds: pass disableCache: true when registering the plugin.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • @fastify/reply-from @fastify/reply-from

    From 8.3.1 · fixed in 12.6.4

References 2

GitHub · fastify/fastify-reply-from

cna.openjsf.org