CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Called exploited 190 days after disclosure.
Measured from the CVE publication date to the earliest of 1 KEV catalogue that list it.
The life of this vulnerability
- CVE published
- First KEV listing6mo
- Last sightingsame day
Gaps are compressed to equal steps. The elapsed time is printed under each.
Which catalogues call it exploited
- CISA KEVUS federaldoes not list it
- EUVDENISA, European Uniondoes not list it
- VulnCheck KEVcommercial researchlisted Sep 26, 2026
- CIRCLaggregator, mirrors the abovedoes not list it
This rests on a single catalogue. No second catalogue corroborates the claim that it is being exploited. CIRCL is an aggregator and is not counted.
Public exploitation evidence
- reported exploitationapi.vulncheck.com/v3/index/vulncheck-canaries?cve=CVE-2026-3
1 public report collected from VulnCheck and CIRCL, first on Sep 26, 2026. Each links to its original source. We have not verified them.
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 rapid