Vulnerability · Published Feb 13, 2026 · Assigned by VulnCheck

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

Medium 5.3

In plain English

A medium-severity cross-site scripting in beautiful-mermaid from lukilabs. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.6%top 52.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	beautiful-mermaid	0.1.3	GHSA-cgmm-x5ww-q5cr

Affected products (as reported)

Vendor	Product	Versions
lukilabs	beautiful-mermaid	0 – before 0.1.3

Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

References

https://github.com/lukilabs/beautiful-mermaid/releases/tag/v0.1.3 release-notes, patch
https://github.com/lukilabs/beautiful-mermaid/pull/8 issue-tracking
https://neo.projectdiscovery.io/share/cec71dc7-a8eb-417e-b8b4-666644796c1e technical-description, exploit
https://www.vulncheck.com/advisories/beautiful-mermaid-svg-attribute-injection third-party-advisory