CVE-2026-120213: @fastify/http-proxy is a Fastify plugin that proxies HTTP requests to an upstream server under a configured pr

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CRITICAL 9.1REMOTE

CVE-2026-120213 is a critical-severity flaw (CVSS 9.1) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

@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 delimite

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	n/a
CISA exploited list	No
Weakness	CWE-22, CWE-436
Published	2026-11-02
Last modified	2026-11-02

Publisher (CNA): openjs

Last updated 2026-11-02 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-11-02 11:17 UTCPublished CVE record published
2026-11-02 11:17 UTCUpdated Record last modified

Advisories and coverage

Research and news

VulDB Recent Entries: CVE-2026-120213 | Fastify http-proxy up to 11.6.5 Rewrite Prefix rewritePrefix server-side request forgery 2026-11-02

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-120213?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-120213 being exploited?

CVE-2026-120213 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-120213 affect?

CVE-2026-120213 affects affected software. Severity is critical (CVSS 9.1). @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

How urgent is CVE-2026-120213?

Priority 37/100. Critical severity; Remotely exploitable, no login, no user action

References

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