REDHAT-BUG-2458651: High severity npm/@fastify/reply-from vulnerability

Published Apr 15, 2026
·
Updated

@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.

Affected Software

2 affected components
npm/@fastify/reply-from<=12.6.1
npm/@fastify/http-proxy<=11.4.3

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade @fastify/reply-from to a version that resolves this vulnerability.

    Fixed in 12.6.2
  2. Upgrade

    Upgrade @fastify/http-proxy to a version that resolves this vulnerability.

    Fixed in 11.4.4

Event History

Apr 15, 2026
Data Sourced
via Red Hat·11:01 AM
DescriptionSeverityAffected Software
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