Medium 6.9Published Dec 1, 2025

CVE-2025-66415fastify-reply-from bypass of reply forwarding

Updated under an hour ago (Oct 28, 2026, 6:10 AM ET)

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It affects fastify-reply-from and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for fastify-reply-from

Exploited in the last 30 days

fastify-reply-from is a Fastify plugin to forward the current HTTP request to another server. Prior to 12.5.0, by crafting a malicious URL, an attacker could access routes that are not allowed, even though the reply.from is defined for specific routes in @fastify/reply-from. This vulnerability is fixed in 12.5.0.

CVSS: 6.9 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness (CWE): CWE-441
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Dec 2, 2025
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

fastify fastify-reply-from fastify:reply_from (from the name)	before 12.5.0	CNA record
fastify reply-from fastify:reply-from	through 12.4.0	NVD

References

References

https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-2q7r-29rg-6m5h	x-refsource-confirm, vendor-advisory
https://github.com/fastify/fastify-reply-from/commit/4d9795cd5b57a36756d37b7f036eae369f69fa66	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.