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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-33805 Detail

Description

@fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests by listing them in the Connection header value. Any header added by the proxy for routing, access control, or security purposes can be selectively removed by a client. @fastify/http-proxy is also affected as it delegates to @fastify/reply-from. Upgrade to @fastify/reply-from v12.6.2 or @fastify/http-proxy v11.4.4 or later.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  openjs
CVSS-B 9.0 CRITICAL
Vector:  CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:L/SI:H/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://cna.openjsf.org/security-advisories.html openjs
https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf74-vj37 CISA-ADP, openjs

Weakness Enumeration

CWE-ID CWE Name Source
CWE-644 Improper Neutralization of HTTP Headers for Scripting Syntax openjs  

Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-33805
NVD Published Date:
04/15/2026
NVD Last Modified:
04/15/2026
Source:
openjs