CVE-2026-93421

Mesop: Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint

Published Sep 23, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-g7f6-rxc4-qhph Mesop: Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint
History
Type Values Removed Values Added
First Time appeared Mesop-dev
Mesop-dev mesop
Vendors & Products Mesop-dev
Mesop-dev mesop
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Mesop: Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint
Weaknesses CWE-117
CWE-150
References
Metrics cvssV4_0

{'score': 5.3, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 23, 2026, 7:41 PM
Reserved
Sep 17, 2026, 8:57 PM
Status
Deferred
Published
Sep 23, 2026, 7:19 PM
Modified
Sep 30, 2026, 5:32 PM