Is there a public exploit for CVE-2026-120214?

No public exploit for CVE-2026-120214 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-2026-120214?

CVE-2026-120214 scores CVSS 5.9 (v3.1), rated medium.

What does CVE-2026-120214 affect?

CVE-2026-120214 affects @fastify/http-proxy @fastify/http-proxy.

5.9 Medium

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

CVE-2026-120214

@fastify/http-proxy is a Fastify plugin that proxies HTTP requests to an upstream server under a configured prefix. In versions 11.6.0 through 11.6.2, the destination validation normalizes literal backslashes before it percent-decodes the request path, so a path that encodes its backslashes and dot-segments survives the dot-segment check and is only turned into backslash and double-dot sequences after that check has passed. When the upstream resolves on a platform that treats a backslash as a path separator, the forwarded request walks out of the configured proxy prefix and reaches a sibling location on the upstream. An unauthenticated remote attacker can use this to retrieve upstream resources outside the intended prefix, so the impact is confidentiality only, and exploitation depends on the upstream's path handling. The issue is fixed in @fastify/http-proxy 11.6.3, and users should upgrade to 11.6.3 or later. This is a follow-up to the earlier prefix-escape fix, which did not account for the encoded-backslash form.

Assessment

CVSS: 5.9 (v3.1)
Severity: Medium
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:H/PR:N/UI:N/S:U/C:H/I:N/A:N

At the source

EUVD (ENISA)

References

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