What’s Vulnerable › Vulnerabilities

CVE-2026-26226: beautiful-mermaid < 0.1.3 SVG Attribute Injection

• Severity: medium (CVSS 5.3 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-13 · updated 2026-10-08
• Weakness: CWE-79

Description

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.

Affected products

• lukilabs beautiful-mermaid: before 0.1.3 — fixed in 0.1.3

How to fix

Upgrade to a fixed version: lukilabs beautiful-mermaid 0.1.3. Check the vendor advisory for mitigations.

References

• https://github.com/lukilabs/beautiful-mermaid/pull/8
• https://github.com/lukilabs/beautiful-mermaid/releases/tag/v0.1.3
• https://neo.projectdiscovery.io/share/cec71dc7-a8eb-417e-b8b4-666644796c1e
• https://www.vulncheck.com/advisories/beautiful-mermaid-svg-attribute-injection

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