CVE-2026-34824CWE-125

Mesop: Unbounded Thread Creation in WebSocket Handler Leads to Denial of Service

High · published April 3, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
51.5
In the wild
Unconfirmed
What it is

Mesop is a Python-based UI framework that allows users to build web applications. From version 1.2.3 to before version 1.2.5, an uncontrolled resource consumption vulnerability exists in the WebSocket implementation of the Mesop framework. An unauthenticated attacker can send a rapid succession of WebSocket messages, forcing the server to spawn an unbounded number of operating system threads. This leads to thread exhaustion and Out of Memory (OOM) errors, causing a complete Denial of Service (DoS) for any application built on the framework. This issue has been patched in version 1.2.5.

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
0.00672 · 51.5th percentile
Weakness
CWE-125 · Out-of-bounds Read
Published
2026-04-03T22:41Z
EPSS history
Timeline
  • 03 APR 22:41Z
    Mesop: Unbounded Thread Creation in WebSocket Handler Leads to Denial of Service
    cvelistv5