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Fencer Vulns
low 3.7

CVE-2026-25224 json

Fastify Vulnerable to DoS via Unbounded Memory Allocation in sendWebStream

published 2026-02-02 9 mo ago modified 2026-06-17 4 mo ago also GHSA-mrq3-vjjr-p77c , EUVD-2026-5158

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 46%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm fastify 5.7.3
  • fastify fastify 5.7.3

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-25224 updated cvss 3.7

Fastify: Fastify: Denial of Service via unbounded buffering in Web Streams response handling

  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/disk-image-cuda-rhel9 Red Hat OpenShift AI (RHOAI) rhoai/odh-dashboard-rhel8, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-model-registry-rhel9 Red Hat OpenShift Dev Spaces devspaces/dashboard-rhel9
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

0.55% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
npm fastify
<5.7.3
5.7.3

Affected products

  • fastify fastify

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.