CVE-2026-26226
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk40th percentile - higher than 40% of all known CVEs
Summary
A vulnerability in beautiful-mermaid prior to version 0.1.3 allows SVG attribute injection, leading to cross-site scripting (XSS) when rendering attacker-controlled Mermaid diagrams. User-controlled values from style and classDef directives are interpolated into SVG attribute values without proper escaping, enabling crafted input to break out of an attribute context and inject arbitrary SVG elements/attributes into the rendered output.
Risk Assessment
The risk involves potential script execution in the context of the embedding page, which could lead to session data theft, account takeover, or other malicious actions in the victim's browser.
Recommendation
Immediately update beautiful-mermaid to version 0.1.3 or later, which contains the fix for this vulnerability.
Original NVD description (English source)
beautiful-mermaid versions prior to 0.1.3 contain an SVG attribute injection issue that can lead to cross-site scripting (XSS) when rendering attacker-controlled Mermaid diagrams. User-controlled values from Mermaid style and classDef directives are interpolated into SVG attribute values without proper escaping, allowing crafted input to break out of an attribute context and inject arbitrary SVG elements/attributes into the rendered output. When the generated SVG is embedded in a web page, this can result in script execution in the context of the embedding origin.