SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2022-39386

Any application using @fastify/websocket could crash if a specific, malformed packet is sent.

HIGH 7.5EPSS 0.80%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.80%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

@fastify/websocket provides WebSocket support for Fastify. Any application using @fastify/websocket could crash if a specific, malformed packet is sent. All versions of fastify-websocket are also impacted. That module is deprecated, so it will not be patched. This has been patched in version 7.1.1 (fastify v4) and version 5.0.1 (fastify v3). There are currently no known workarounds. However, it should be possible to attach the error handler manually. The recommended path is upgrading to the patched versions.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
0.80% probability · 56th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-248
Affected
fastify/websocket
Source
security-advisories@github.com
EPSS trend
0%3%5%26 October 2026: 0.80%26 October 202626 October 2026

EPSS 0.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.