TI-2026-21217 Aliases CVE-2026-26226 GHSA-cgmm-x5ww-q5cr

beautiful-mermaid < 0.1.3 SVG Attribute Injection

MEDIUM 57CWE-79Published 2026-02-13 · Updated 2026-11-08

Key facts

Attack vector: Network
Privileges required: None
User interaction: Passive
Attack complexity: Low
Attack requirements: None
Impact type: Cross-site scripting
Confidentiality · integrity · availability: Low · Low · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00573 47th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by the CNA

Fix Fixed beautiful-mermaid (lukilabs): 0.1.3beautiful-mermaid (npm): 0.1.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
lukilabs	beautiful-mermaid	before 0.1.3	0.1.3	Patch available	CNA
—	beautiful-mermaid (npm)	before 0.1.3	0.1.3	Patch available	GHSA-cgmm-x5ww-q5cr

beautiful-mermaid Vendorlukilabs Affected before 0.1.3 Fixed in 0.1.3 Patch available CNA
beautiful-mermaid (npm) Vendor— Affected before 0.1.3 Fixed in 0.1.3 Patch available GHSA-cgmm-x5ww-q5cr

Remediation

Fix · CNA beautiful-mermaid (lukilabs) Fixed in 0.1.3
Fix · GHSA-cgmm-x5ww-q5cr beautiful-mermaid (npm) Fixed in 0.1.3 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-26226
2026-10-03 Alias added: GHSA-cgmm-x5ww-q5cr
2026-10-25 EPSS moved to the below the 50th percentile

References

Exploit 1

https://neo.projectdiscovery.io/share/cec71dc7-a8eb-417e-b8b4-666644796c1e

Patch 2

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-26226

Other 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences