CVE-2025-30358 Mesop Class Pollution vulnerability leads to DoS and Jailbreak attacks
Attackers can pollute classes to cause denial of service, impersonate roles, or potentially execute code in Mesop applications.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-30358?
CVE-2025-30358 is a high-severity code injection vulnerability in mesop-dev mesop, published on 27 Mar 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-915
Which versions are affected by CVE-2025-30358?
3 open source packages ship an affected version, including mesop.
| Package | Affected | Fixed in |
|---|---|---|
mesop PyPI | All versions | 0.14.1 |
mesop PyPI | All versions | 0.14.1 |
mesop PyPI | All versions | 0.14.1 |
How do I fix CVE-2025-30358?
Upgrade mesop to 0.14.1 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2025-30358 being exploited?
There is no known exploitation of CVE-2025-30358 in the wild and no public exploit code.
Sources
Also known as GHSA-f3mf-hm6v-jfhh, PYSEC-2026-1624.