Is there a public exploit for CVE-2026-120213?

No public exploit for CVE-2026-120213 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-120213?

CVE-2026-120213 scores CVSS 9.1 (v3.1), rated critical.

What does CVE-2026-120213 affect?

CVE-2026-120213 affects @fastify/http-proxy @fastify/http-proxy.

9.1 Critical

@fastify/http-proxy is a Fastify plugin that proxies HTTP requests to an upstream server under a configured prefix.

CVE-2026-120213

@fastify/http-proxy is a Fastify plugin that proxies HTTP requests to an upstream server under a configured prefix. In versions 9.0.0 through 11.6.5, when an application uses parameterized prefix and rewritePrefix options to pin clients to a fixed upstream path, the plugin substitutes URL-decoded route parameters into rewritePrefix without re-encoding them. A parameter value that encodes a path separator together with a fragment or query delimiter therefore decodes into real separators and delimiters that inject extra upstream path segments and strip the mandatory suffix the rewritePrefix was meant to enforce, without using any dot-dot traversal. An unauthenticated remote attacker can use this to reach upstream locations outside the intended prefix, leading to path-restriction bypass and, depending on the upstream, server-side request forgery or authorization bypass in the proxied service. The issue is fixed in @fastify/http-proxy 11.6.6, and users should upgrade to 11.6.6 or later. There is no workaround other than upgrading.

Assessment

CVSS: 9.1 (v3.1)
Severity: Critical
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 2 November 2026
Last updated: 2 November 2026
Affected: @fastify/http-proxy · @fastify/http-proxy
Assigner: openjs

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

At the source

EUVD (ENISA)

References

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