CVE-2025-5399

WebSocket endless loop

High · published June 7, 2025

CVSS v3.1
7.5
EPSS
1%
Percentile
71.8
In the wild
Unconfirmed
What it is

Due to a mistake in libcurl's WebSocket code, a malicious server can send a

particularly crafted packet which makes libcurl get trapped in an endless

busy-loop.

There is no other way for the application to escape or exit this loop other

than killing the thread/process.

This might be used to DoS libcurl-using application.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.01376 · 71.8th percentile
Published
2025-06-07T07:49Z
EPSS history
Timeline
  • 07 JUN 07:49Z
    WebSocket endless loop
    cvelistv5