---
id: CVE-2026-77357
title: >-
  Mesop is a Python-based UI framework that allows users to build web
  applications
summary: >-
  Mesop is a Python-based UI framework that allows users to build web
  applications. Prior to 1.3.3, applications running in debug mode expose a GET
  /hot-reload endpoint whose unbounded loop depends on the user-supplied counter
  parameter, a…
severity: none
cwe:
  - CWE-400
  - CWE-834
published: '2026-08-25'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:09:13.080'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77357'
references:
  - url: >-
      https://github.com/mesop-dev/mesop/commit/2b8e7f2c349c9e2eec202f46b07bada83061ce2d
    label: security-advisories@github.com
  - url: 'https://github.com/mesop-dev/mesop/releases/tag/v1.3.3'
    label: security-advisories@github.com
  - url: 'https://github.com/mesop-dev/mesop/security/advisories/GHSA-8p72-497j-83mx'
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00529
epssPercentile: 0.42257
ingestedAt: '2026-09-09T21:22:45.553Z'
---

## Overview

Mesop is a Python-based UI framework that allows users to build web applications. Prior to 1.3.3, applications running in debug mode expose a GET /hot-reload endpoint whose unbounded loop depends on the user-supplied counter parameter, allowing an unauthenticated attacker to hold worker threads with high counter values until the worker pool is exhausted and the server becomes unavailable. A single unauthenticated attacker can crash the Mesop server with minimal effort. Because the attack leverages worker exhaustion, the server remains unresponsive until it is manually restarted. This issue is fixed in version 1.3.3.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.