CVE-2026-77357

Mesop: DoS in /hot-reload endpoint allows unauthenticated attacker to exhaust worker threads and crash the server

Published Aug 25, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
Description
Mesop is a Python-based UI framework that allows users to build web applications. Prior to 1.3.3, applications running in debug mode expose a GET /hot-reload endpoint whose unbounded loop depends on the user-supplied counter parameter, allowing an unauthenticated attacker to hold worker threads with high counter values until the worker pool is exhausted and the server becomes unavailable. A single unauthenticated attacker can crash the Mesop server with minimal effort. Because the attack leverages worker exhaustion, the server remains unresponsive until it is manually restarted. This issue is fixed in version 1.3.3.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

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
Description Mesop is a Python-based UI framework that allows users to build web applications. Prior to 1.3.3, applications running in debug mode expose a GET /hot-reload endpoint whose unbounded loop depends on the user-supplied counter parameter, allowing an unauthenticated attacker to hold worker threads with high counter values until the worker pool is exhausted and the server becomes unavailable. A single unauthenticated attacker can crash the Mesop server with minimal effort. Because the attack leverages worker exhaustion, the server remains unresponsive until it is manually restarted. This issue is fixed in version 1.3.3.
Title Mesop: DoS in /hot-reload endpoint allows unauthenticated attacker to exhaust worker threads and crash the server
Weaknesses CWE-400
CWE-834
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 26, 2026, 12:54 PM
Reserved
Aug 20, 2026, 7:28 PM
Status
Deferred
Published
Aug 25, 2026, 9:17 PM
Modified
Sep 9, 2026, 9:09 PM