@fastify/reply-from is a Fastify plugin that forwards requests to an upstream HTTP or HTTPS server. In versions prior to 12.7.0, all of the built-in HTTPS transports override the secure default and set rejectUnauthorized to false, so the proxy does not verify the TLS certificate of the upstream even when the application points it at an https upstream in the default configuration. An on-path network attacker can therefore impersonate the configured HTTPS upstream, read the credentials and request bodies the proxy forwards, and return forged responses that the application trusts. The issue is fixed in @fastify/reply-from 12.7.0, and users should upgrade to 12.7.0 or later. As a workaround, pass an explicit rejectUnauthorized true on the transport, supply an already configured undici instance, or use the undici global agent.
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Fixes

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History

Thu, 08 Oct 2026 20:45:00 +0000

Type Values Removed Values Added
Description @fastify/reply-from is a Fastify plugin that forwards requests to an upstream HTTP or HTTPS server. In versions prior to 12.7.0, all of the built-in HTTPS transports override the secure default and set rejectUnauthorized to false, so the proxy does not verify the TLS certificate of the upstream even when the application points it at an https upstream in the default configuration. An on-path network attacker can therefore impersonate the configured HTTPS upstream, read the credentials and request bodies the proxy forwards, and return forged responses that the application trusts. The issue is fixed in @fastify/reply-from 12.7.0, and users should upgrade to 12.7.0 or later. As a workaround, pass an explicit rejectUnauthorized true on the transport, supply an already configured undici instance, or use the undici global agent.
Title @fastify/reply-from vulnerable to improper certificate validation in built-in HTTPS transports
Weaknesses CWE-295
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published:

Updated: 2026-10-08T20:32:03.483Z

Reserved: 2026-10-07T17:27:41.901Z

Link: CVE-2026-107318

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-08T21:17:51.807

Modified: 2026-10-08T21:35:53.890

Link: CVE-2026-107318

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-08T21:30:18Z

Weaknesses