CVE-2026-93421

Mesop: Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint

MEDIUM
5.3
CVSS Score
Published: September 23, 2026 at 06:59 PM UTC
Updated: September 30, 2026 at 05:32 PM UTC
1 product affected across 1 vendorMesop

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.3.4
Affected range stops below 1.3.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-117CWE-150

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