CVE-2026-33805
Published: Apr 15, 2026
Modified: Apr 15, 2026
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.
| Vendor | Product | Versions |
|---|---|---|
@fastify/reply-from | @fastify/reply-from | affected 0 - < 12.6.2unaffected 12.6.2 |
@fastify/reply-from | @fastify/http-proxy | affected 0 - < 11.4.4unaffected 11.4.4 |
Weaknesses (CWE)
Security Training
Train your team to recognize and prevent security threats with our comprehensive security awareness program.
Start TrainingVulnerability Scanning
Discover vulnerabilities in your applications and infrastructure before attackers do.
Scan Now