CVE-2025-30358
Mesop Class Pollution vulnerability leads to DoS and Jailbreak attacks
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.1
Mesop Class Pollution vulnerability leads to DoS and Jailbreak attacks
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.
- Record
CVE-2025-30358- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-915
- Updated
- 2026-11-02
EUVDEUVD-2025-14804
8.1
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.
- Record
EUVD-2025-14804- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-f3mf-hm6v-jfhh
8.1
Mesop Class Pollution vulnerability leads to DoS and Jailbreak attacks
From @jackfromeast and @superboy-zjc: We have identified a class pollution vulnerability in Mesop (<= 0.14.0) application that 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 consequnces like RCE when gadgets are available.
- Record
GHSA-f3mf-hm6v-jfhh- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-915
- Updated
- 2026-11-02
NVD
8.1
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.
- Record
CVE-2025-30358- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-915
- Updated
- 2026-11-02
OSV
8.1
Mesop Class Pollution vulnerability leads to DoS and Jailbreak attacks
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.
- Record
CVE-2025-30358- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-915
- Updated
- 2026-11-02
OSVGHSA-f3mf-hm6v-jfhh
8.1
Mesop Class Pollution vulnerability leads to DoS and Jailbreak attacks
From @jackfromeast and @superboy-zjc: We have identified a class pollution vulnerability in Mesop (<= 0.14.0) application that 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 consequnces like RCE when gadgets are available.
- Record
GHSA-f3mf-hm6v-jfhh- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-915
- Updated
- 2026-11-02
OSVPYSEC-2026-1624
8.1
Mesop Class Pollution vulnerability leads to DoS and Jailbreak attacks
From @jackfromeast and @superboy-zjc: We have identified a class pollution vulnerability in Mesop (<= 0.14.0) application that 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 consequnces like RCE when gadgets are available.
- Record
PYSEC-2026-1624- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mesopPyPI |
before 0.14.1 | 0.14.1 |
mesopPyPI |
before 0.14.1, plus listed versions 0.0.10.10.00.10.0rc00.10.0rc10.10.0rc2 Show 45 moreShow less0.11.00.11.0rc00.11.10.12.00.12.0rc00.12.10.12.10b10.12.10b20.12.10b30.12.10rc10.12.1rc00.12.20.12.30.12.3rc00.12.40.12.4rc00.12.50.12.5b10.12.5rc10.12.60.12.6rc10.12.70.12.7b10.12.7rc10.12.80.12.8b10.12.8rc10.12.90.12.9rc10.13.00.13.0rc10.14.00.14.1rc10.14rc10.3.10.3.20.3.30.3.40.4.00.4.10.4.20.5.00.5.10.5.20.5.3 |
0.14.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-30358 is a high vulnerability (CVSS 8.1) in Mesop-dev Mesop, published March 27, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.71%, the 53rd percentile. Fixed in mesop 0.14.1.
References
github.com/mesop-dev/mesop/security/advisories/GHSA-f3mf-hm6v-jfhh
github.com/mesop-dev/mesop/commit/748e20d4a363d89b841d62213f5b0c6b4bed788f
nvd.nist.gov/vuln/detail/CVE-2025-30358
github.com/advisories/GHSA-f3mf-hm6v-jfhh
github.com/CVEProject/cvelistV5/tree/main/cves/2025/30xxx/CVE-2025-30358.json
github.com/mesop-dev/mesop
pypi.org/project/mesop
Left out here: 21 versions. The JSON record has them.