CVE-2024-26151

Workarounds

• Ensure that potentially untrusted user input does not contain any sequences which could be rendered as HTML.

References

• Initial issue report by @sh-at-cs in #52

All users of mjml-python who insert untrusted data into mjml templates unless that data is checked in a very strict manner. User input like <script> would be rendered as <script> in the final HTML output.

The attacker must be able to control some data which is later injected in an mjml template which is then send out as email to other users. The attacker could control contents of email messages sent through the platform.

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

CVE-2024-26151 has a CVSS score of 8.2 (High). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.11.0); upgrading removes the vulnerable code path.

Kodem intelligence

The problem has been fixed in version 0.11.0 of this library. Versions before 0.10.0 are not affected by this security issue which was added as part of commit 84c495da20a91640a1ca551ace17df7f3be644aa.

1. What is CVE-2024-26151? CVE-2024-26151 is a high-severity improper input validation vulnerability in mjml (pip), affecting versions = 0.10.0. It is fixed in 0.11.0. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
2. How severe is CVE-2024-26151? CVE-2024-26151 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of mjml are affected by CVE-2024-26151? mjml (pip) versions = 0.10.0 is affected.
4. Is there a fix for CVE-2024-26151? Yes. CVE-2024-26151 is fixed in 0.11.0. Upgrade to this version or later.
5. Is CVE-2024-26151 exploitable, and should I be worried? Whether CVE-2024-26151 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2024-26151 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2024-26151? Upgrade mjml to 0.11.0 or later.