TI-2025-21664 Aliases CVE-2025-30358 GHSA-f3mf-hm6v-jfhh

Mesop Class Pollution vulnerability leads to DoS and Jailbreak attacks

LOW 36CWE-915Published 2025-03-27 · Updated 2025-03-27

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Tampering
Confidentiality · integrity · availability: None · High · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-915.

Summary

Mesop is a Python-based UI framework that allows users to build web applications. A class pollution vulnerability in Mesop prior to version 0.14.1 allows attackers to overwrite global variables and class attributes in certain Mesop modules during runtime. This vulnerability could directly lead to a denial of service (DoS) attack against the server. Additionally, it could also result in other severe consequences given the application's implementation, such as identity confusion, where an attacker could impersonate an assistant or system role within conversations. This impersonation could potentially enable jailbreak attacks when interacting with large language models (LLMs). Just like the Javascript's prototype pollution, this vulnerability could leave a way for attackers to manipulate the intended data-flow or control-flow of the application at runtime and lead to severe consequences like remote code execution when gadgets are available. Users should upgrade to version 0.14.1 to obtain a fix for the issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0071 53rd percentileScored 2026-11-07

Fix Fixed mesop (mesop-dev): 0.14.1mesop (PyPI): 0.14.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
mesop-dev	mesop	before 0.14.1	0.14.1	Patch available	CNA
—	mesop (PyPI)	before 0.14.1	0.14.1	Patch available	GHSA-f3mf-hm6v-jfhh

mesop Vendormesop-dev Affected before 0.14.1 Fixed in 0.14.1 Patch available CNA
mesop (PyPI) Vendor— Affected before 0.14.1 Fixed in 0.14.1 Patch available GHSA-f3mf-hm6v-jfhh

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:mesop-dev:mesop::::::::	—	—	mesop-dev

cpe:2.3:a:mesop-dev:mesop:*:*:*:*:*:*:*:* Versions — — ·mesop-dev

Remediation

Fix · CNA mesop (mesop-dev) Fixed in 0.14.1
Fix · GHSA-f3mf-hm6v-jfhh mesop (PyPI) Fixed in 0.14.1 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2025-30358
2026-10-03 Alias added: GHSA-f3mf-hm6v-jfhh

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2025-30358

Other 3

TI-2026-25500 Mesop Affected by Unauthenticated Remote Code Execution via Test Suite Route /exec-py CVSS 3.1CRITICAL 9.8
TI-2026-25497 Mesop: Path Traversal utilizing `FileStateSessionBackend` leads to Application Denial of Service and File Write/Deletion CVSS 3.1CRITICAL 10.0
TI-2026-53977 Mesop: DoS in /hot-reload endpoint allows unauthenticated attacker to exhaust worker threads and crash the server CVSS 4.0HIGH 8.7
TI-2026-27068 Mesop: Unbounded Thread Creation in WebSocket Handler Leads to Denial of Service CVSS 3.1HIGH 7.5
TI-2026-62971 Mesop: Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint CVSS 4.0MEDIUM 5.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences