CVE-2026-41149: Code Injection

Description

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Versions 10.9.5 and earlier, as well as 11.0.0-alpha.1 through 11.14.0, are vulnerable to HTML injection under the default configuration. Specifically, the classDef directive in Mermaid state diagrams permits DOM injection that escapes the SVG context. However, <script> tags are stripped, which prevents cross-site scripting (XSS). This issue has been fixed in versions 10.9.6 and 11.15.0. If developers are unable to immediately upgrade, they can work around this issue by setting "securityLevel": "sandbox", which prevents the issue by rendering the mermaid diagram in a sandboxed <iframe>.

Is your site exposed to CVE-2026-41149?

Run a free security scan — no signup, results in seconds.

EPSS — Exploit Prediction

0.0052

Probability of exploitation

0.40%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-94 CWE-94

References

Other References

https://github.com/mermaid-js/mermaid/commit/37ff937f1da2e19f882fd1db01235db4d01f4056 https://github.com/mermaid-js/mermaid/commit/4e2d512bf5bf6f9de1a8f0a48da78dc4d09ac4f3 https://github.com/mermaid-js/mermaid/security/advisories/GHSA-ghcm-xqfw-q4vr https://github.com/mermaid-js/mermaid/security/advisories/GHSA-ghcm-xqfw-q4vr

Frequently Asked Questions

What is CVE-2026-41149? +

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Versions 10.9.5 and earlier, as well as 11.0.0-alpha.1 through 11.14.0, are vulnerable to HTML injection under the default configuration. Specifically, the classDef directive in Mermaid state diagrams permits DOM injection that escapes the SVG context. However, <script> tags are stripped, which prevents cross-site scripting (XSS). This issue has been fixed in versions 10.9.6 and 11.15.0. If developers are unable to immediately upgrade, they can work around this issue by setting "securityLevel": "sandbox", which prevents the issue by rendering the mermaid diagram in a sandboxed <iframe>.

How do I check if I'm vulnerable to CVE-2026-41149? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-22136

Tabby (formerly Terminus) is a highly configurable terminal emulator. Prior to 1.0.217 , Tabby enables several high-risk Electron Fuses, including …

CVE-2025-24482

A Local Code Injection Vulnerability exists in the product and version listed above. The vulnerability is due to incorrect default …

CVE-2026-42890

Actual is an open-source personal finance application. In the macOS desktop application version 25.x (built on Electron 39.2.7), the ELECTRON_RUN_AS_NODE …

CVE-2026-53511

calibre is an e-book manager. Prior to 9.10.0, a malicious EPUB, OPF, or PDF file can execute arbitrary Python code …

CVE-2026-43921

FOSSBilling is a free, open-source billing and client management system. Versions 0.6.10 through 0.7.2 have a PHP code injection vulnerability …

CVE-2025-24959

zx is a tool for writing better scripts. An attacker with control over environment variable values can inject unintended environment …

CVE-2026-41149