# CVE-2026-34824: mesop-dev Mesop uncontrolled resource consumption in WebSocket handler

Source: https://junglewise.ai/threats/cve-2026-34824-mesop-dev-mesop-uncontrolled-resource-consumption-in-websocket  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-03. Updated: 2026-07-25  
License: CC BY 4.0 with a link back

CVE-2026-34824 · Severity: high · CVSS 7.5 · Published 2026-04-03

Mesop is a Python framework used by developers to build web-based user interfaces. A security flaw in how the framework handles real-time communications (WebSockets) allows an attacker to crash the application by sending a flood of messages. This results in a total service outage, making the application unavailable to legitimate users and potentially crashing the server it runs on.

Technologies: [mesop (PyPI)](https://junglewise.ai/threats/technologies/mesop). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-34824 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34824 being exploited in the wild.

**How severe is CVE-2026-34824?** High severity, with a CVSS score of 7.5, published 3 April 2026.

**Which products and versions are affected?** mesop (PyPI) >= 1.2.3, < 1.2.5, ECOSYSTEM:introduced=1.2.3,fixed=1.2.5.

**Is there a fix for CVE-2026-34824?** Yes. mesop (PyPI): upgrade to 1.2.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-34824 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-34824?** Check whether you run mesop (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- mesop (PyPI): upgrade to 1.2.5 or later

  ```sh
  pip install "mesop>=1.2.5"
  ```


## Technical details

An uncontrolled resource consumption vulnerability (CWE-400) exists in the Mesop framework's WebSocket handler within `mesop/server/server.py`. The `handle_websocket` function fails to implement rate limiting or thread pooling, instead spawning a new `threading.Thread` for every incoming `ui_request`. A remote, unauthenticated attacker can exploit this by sending a high volume of WebSocket messages in rapid succession. This leads to the exhaustion of operating system threads and memory (OOM), resulting in a complete Denial of Service (DoS). The vulnerability is addressed in version 1.2.5 by bounding concurrent WebSocket threads per connection.

## Affected products

- mesop-dev Mesop >= 1.2.3, < 1.2.5

## Identifiers

- CVE-2026-34824
- GHSA-3jr7-6hqp-x679
- PYSEC-2026-2204

## Timeline

- 2026-03-31: patched: Version 1.2.5 released
- 2026-04-02: advisory: GitHub Security Advisory published
- 2026-04-03: disclosed: CVE published to NVD

## References

- [https://github.com/mesop-dev/mesop/commit/760a2079b5c609038c826d24dfbcf9b0be98d987](https://github.com/mesop-dev/mesop/commit/760a2079b5c609038c826d24dfbcf9b0be98d987)
- [https://github.com/mesop-dev/mesop/releases/tag/v1.2.5](https://github.com/mesop-dev/mesop/releases/tag/v1.2.5)
- [https://github.com/mesop-dev/mesop/security/advisories/GHSA-3jr7-6hqp-x679](https://github.com/mesop-dev/mesop/security/advisories/GHSA-3jr7-6hqp-x679)

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