Medium 5.3Published Sep 23, 2026

CVE-2026-93421Mesop: Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint

Updated under an hour ago (2026-10-19 10:50 UTC)

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It affects mesop-dev mesop. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for mesop-dev mesop

Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v4.0, CNA)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
Weakness (CWE): CWE-117, CWE-150
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Sep 23, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

mesop-dev mesop mesop_dev:mesop (from the name)	before 1.3.4	CNA record

References

https://github.com/mesop-dev/mesop/security/advisories/GHSA-g7f6-rxc4-qhphx-refsource-confirm
https://github.com/mesop-dev/mesop/pull/1397x-refsource-misc
https://github.com/mesop-dev/mesop/commit/f38c42a1d3eba246941ef8d7f645072d53c58785x-refsource-misc
https://github.com/mesop-dev/mesop/releases/tag/v1.3.4x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.