Vulnerability · Published Mar 20, 2026 · Assigned by GitHub_M
CVE-2026-33057Mesop Affected by Unauthenticated Remote Code Execution via Test Suite Route /exec-py
Critical 9.8
In plain English
A critical-severity code injection in mesop from mesop-dev. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 5.4% (higher than 93% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
Mesop is a Python-based UI framework that allows users to build web applications. In versions 1.2.2 and below, an explicit web endpoint inside the ai/ testing module infrastructure directly ingests untrusted Python code strings unconditionally without authentication measures, yielding standard Unrestricted Remote Code Execution. Any individual capable of routing HTTP logic to this server block will gain explicit host-machine command rights. The AI codebase package includes a lightweight debugging Flask server inside ai/sandbox/wsgi_app.py. The /exec-py route accepts base_64 encoded raw string payloads inside the code parameter natively evaluated by a basic POST web request. It saves it rapidly to the operating system logic path and injects it recursively using execute_module(module_path...). This issue has been fixed in version 1.2.3.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | mesop | 1.2.3 | GHSA-gjgx-rvqr-6w6v |
| PyPI | mesop | 1.2.3 | PYSEC-2026-412 |
Affected products (as reported)
Weakness: CWE-94 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H