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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-41159

25
FAUCET Score

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Prior to 10.9.6 and 11.15.0, Mermaid's default configuration allows injecting CSS that applies outside of the Mermaid diagram via the fontFamily, themeCSS, and altFontFamily configuration options. The injected CSS exploits stylis's & (scope reference) handling. :not(&) escapes the #mermaid-xxx automatic scoping, applying styles to all page elements. Global at-rules (@font-face, @keyframes, @counter-style) are also injectable as stylis hoists them to top level. This allows page defacement and DOM attribute exfiltration via CSS :has() selectors. This vulnerability is fixed in 10.9.6 and 11.15.0.

First published: May 29, 2026Last modified: Jul 1, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 10.9.6CPE matchmatch criteria
cpe:2.3:a:mermaid_project:mermaid:*:*:*:*:*:node.js:*:*
>= 11.0.0, < 11.15.0CPE matchmatch criteria
cpe:2.3:a:mermaid_project:mermaid:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 4.0

5.3MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L/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

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
VS Confidentiality
NONE
VS Integrity
LOW
VS Availability
NONE
SS Confidentiality
LOW
SS Integrity
LOW
SS Availability
LOW
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.40%
Probability of exploitation in next 30 days
EPSS Percentile
32.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0040 is in the 20th percentile among its peer group of 23,723 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

github_advisorypatch availablevia nvd_reference
View patch
npmpatch availablevia ghsa
Product: mermaidFixed in: 11.15.0
npmpatch availablevia ghsa
Product: mermaidFixed in: 10.9.6

Vendor Advisories (1)

npmGHSA-87f9-hvmw-gh4pmedium

Mermaid: Improper sanitization of configuration leads to CSS injection

May 11, 2026

References

github.com / mermaid-js/mermaid/commit/64769738d5b59211e1decb471ffbaca8afec51aa
github.com / mermaid-js/mermaid/commit/a9d9f0d8eb790349121508688cd338253fd80d76
github.com / mermaid-js/mermaid/releases/tag/[email protected]
Release Notes
github.com / mermaid-js/mermaid/releases/tag/v10.9.6
Release Notes
github.com / mermaid-js/mermaid/security/advisories/GHSA-87f9-hvmw-gh4p
Third Party Advisory