CVE-2026-93421

Mesop: Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint

State: Published
Severity: 5.3 Medium
Published: Sep 23, 2026
Updated: Sep 23, 2026
Reserved: Sep 17, 2026

Description

Mesop is a Python-based UI framework that allows users to build web applications. Prior to 1.3.4, the unauthenticated /__csp__ endpoint passes attacker-controlled document-uri, blocked-uri, and violated-directive values to the csp_report handler in mesop/server/static_file_serving.py, which prints them to standard output without neutralizing terminal control sequences. When an operator views the resulting logs in an ANSI-capable terminal, injected ANSI or VT100 sequences can clear or reposition the display, hide text, or present forged messages, reducing the integrity of monitoring and incident-response output. This issue is fixed in version 1.3.4.

Scores

CVSS	Score	Vector	Source
4.0	5.3 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N	GitHub_M

Weaknesses

CWE-117 Improper Output Neutralization for Logs
CWE-150 Improper Neutralization of Escape, Meta, or Control Sequences

Affected Products

Product	Versions
mesopmesop-dev	< 1.3.4Affected

References

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