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CVE-2026-33054

CRITICAL CVSS 3.1: 9.8 EPSS 0.02%
Updated Mar 24, 2026
Mesop-Dev
Parameter Value
CVSS 9.8 (CRITICAL)
Affected Versions before 1.2.3
Fixed In 1.2.3
Type CWE-22 (Path Traversal)
Vendor Mesop-Dev
Public PoC No

Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation.

This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Mesop-Dev Mesop
cpe:2.3:a:mesop-dev:mesop:*:*:*:*:*:*:*:*
1.2.3

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