How severe is CVE-2025-66415?

CVE-2025-66415 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2025-66415 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66415?

CVE-2025-66415 affects Fastify Reply-from. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-66415?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-66415 have an EU (EUVD) identifier?

Yes. CVE-2025-66415 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-200117.

When was CVE-2025-66415 published?

CVE-2025-66415 was published on 2025-12-01 and last updated on 2026-06-17.

CVE-2025-66415

CVE-2025-66415 is a medium-severity vulnerability in Fastify Reply-from with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-441.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v4: 6.9
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-200117
Weakness: CWE-441
Affected product: Fastify Reply-from
Published: 2025-12-01
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2025-66415?: 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.
How severe is CVE-2025-66415?: CVE-2025-66415 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-66415 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66415?: CVE-2025-66415 affects Fastify Reply-from. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-66415?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-66415 have an EU (EUVD) identifier?: Yes. CVE-2025-66415 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-200117.
When was CVE-2025-66415 published?: CVE-2025-66415 was published on 2025-12-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:fastify:reply-from:*:*:*:*:*:node.js:*:*

More vulnerabilities in Fastify Reply-from

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