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CVE-2026-26226

MEDIUMCVSS 5.3/10EPSS 0.51%

Last modified

CVE-2026-26226 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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. EPSS estimates a 0.51% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 4.0
5.3/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.51%

39.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-26226?
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.
How severe is CVE-2026-26226?
CVE-2026-26226 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.51% probability of exploitation in the next 30 days.
How do I fix CVE-2026-26226?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-26226?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST