How severe is CVE-2026-25224?

CVE-2026-25224 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2026-25224 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-25224?

CVE-2026-25224 affects Fastify. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-25224?

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

Does CVE-2026-25224 have an EU (EUVD) identifier?

Yes. CVE-2026-25224 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5158.

When was CVE-2026-25224 published?

CVE-2026-25224 was published on 2026-02-03 and last updated on 2026-06-17.

CVE-2026-25224

CVE-2026-25224 is a low-severity vulnerability in Fastify with a CVSS 3.x base score of 3.7. 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-770.

Key facts

Severity: Low (CVSS 3.x base score 3.7)
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-5158
Weakness: CWE-770
Affected product: Fastify
Published: 2026-02-03
Last modified: 2026-06-17

Description

Fastify is a fast and low overhead web framework, for Node.js. Prior to version 5.7.3, a denial-of-service vulnerability in Fastify’s Web Streams response handling can allow a remote client to exhaust server memory. Applications that return a ReadableStream (or Response with a Web Stream body) via reply.send() are impacted. A slow or non-reading client can trigger unbounded buffering when backpressure is ignored, leading to process crashes or severe degradation. This issue has been patched in version 5.7.3.

Frequently asked questions

What is CVE-2026-25224?: Fastify is a fast and low overhead web framework, for Node.js. Prior to version 5.7.3, a denial-of-service vulnerability in Fastify’s Web Streams response handling can allow a remote client to exhaust server memory. Applications that return a ReadableStream (or Response with a Web Stream body) via reply.send() are impacted. A slow or non-reading client can trigger unbounded buffering when backpressure is ignored, leading to process crashes or severe degradation. This issue has been patched in version 5.7.3.
How severe is CVE-2026-25224?: CVE-2026-25224 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2026-25224 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-25224?: CVE-2026-25224 affects Fastify. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-25224?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-25224 have an EU (EUVD) identifier?: Yes. CVE-2026-25224 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5158.
When was CVE-2026-25224 published?: CVE-2026-25224 was published on 2026-02-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:fastify:fastify:*:*:*:*:*:node.js:*:*

More vulnerabilities in Fastify

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CVE-2026-25223 — High (CVSS 7.5): Fastify is a fast and low overhead web framework, for Node.js. Prior to version 5.7.2, a validation bypass…
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