@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.
References
| Link | Resource |
|---|---|
| https://cna.openjsf.org/security-advisories.html | Vendor Advisory |
| https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf74-vj37 | Exploit Mitigation Vendor Advisory |
| https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf74-vj37 | Exploit Mitigation Vendor Advisory |
Configurations
Configuration 1 (hide)
|
History
01 Jun 2026, 14:51
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 8.6 |
| First Time |
Fastify reply-from
Fastify Fastify fastify\/http-proxy |
|
| CPE | cpe:2.3:a:fastify:fastify\/http-proxy:*:*:*:*:*:node.js:*:* cpe:2.3:a:fastify:reply-from:*:*:*:*:*:node.js:*:* |
|
| References | () https://cna.openjsf.org/security-advisories.html - Vendor Advisory | |
| References | () https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf74-vj37 - Exploit, Mitigation, Vendor Advisory |
15 Apr 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-15 11:16
Updated : 2026-06-01 14:51
NVD link : CVE-2026-33805
Mitre link : CVE-2026-33805
CVE.ORG link : CVE-2026-33805
JSON object : View
Products Affected
fastify
- reply-from
- fastify\/http-proxy
CWE
CWE-644
Improper Neutralization of HTTP Headers for Scripting Syntax