RCE in Mesop-Dev Mesop

CVE-2026-33057

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.

Vulnerability class: RCE (Remote Code Execution)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.041 (90.5th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 90.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-33057: fell from 0.053 to 0.041.

EPSS over last 30 days · oldest: 0.053 · newest: 0.041 · change: -0.012

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-33057?
CVE-2026-33057 is a critical-severity vulnerability in Mesop-Dev Mesop, classified under Code Injection. CVSS score: 9.8/10. Published 2026-03-20.
How severe is CVE-2026-33057?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-33057 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.