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Medium · 5.3 CVE-2026-93421 EUVD-2026-85568GHSA-g7f6-rxc4-qhphPYSEC-2026-4105

Mesop: Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint

Published Sep 23, 2026 · Updated Sep 23, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
mesop-dev mesop < 1.3.4 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI mesop < 1.3.4 1.3.4 GHSA-g7f6-rxc4-qhph

References