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TI-2026-29777 Aliases CVE-2026-41149GHSA-ghcm-xqfw-q4vr

Mermaid: Improper sanitization of `classDef` in state diagrams leads to HTML injection

Priority MEDIUM 57CWE-94Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
None · Low · None
Fix status
Partial Red Hat: 2 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-94.

Summary

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Versions 10.9.5 and earlier, as well as 11.0.0-alpha.1 through 11.14.0, are vulnerable to HTML injection under the default configuration. Specifically, the classDef directive in Mermaid state diagrams permits DOM injection that escapes the SVG context. However, <script> tags are stripped, which prevents cross-site scripting (XSS). This issue has been fixed in versions 10.9.6 and 11.15.0. If developers are unable to immediately upgrade, they can work around this issue by setting "securityLevel": "sandbox", which prevents the issue by rendering the mermaid diagram in a sandboxed <iframe>.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00401 34th percentileScored 2026-11-07
Fix Partial mermaid (mermaid-js): 11.15.0, 10.9.6mermaid (npm): 11.15.0, 10.9.6Red Hat: 2 without a fix

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

VendorProductAffected versionsFixed inStatusSource
mermaid-jsmermaid11.0.0-alpha.1 to before 11.15.0; before 10.9.611.15.0, 10.9.6Patch availableCNA
—mermaid (npm)11.0.0-alpha.1 to before 11.15.011.15.0Patch availableGHSA-ghcm-xqfw-q4vr
—mermaid (npm)before 10.9.610.9.6Patch availableGHSA-ghcm-xqfw-q4vr
  • mermaid Vendormermaid-js Affected 11.0.0-alpha.1 to before 11.15.0; before 10.9.6 Fixed in 11.15.0, 10.9.6 Patch available CNA
  • mermaid (npm) Vendor— Affected 11.0.0-alpha.1 to before 11.15.0 Fixed in 11.15.0 Patch available GHSA-ghcm-xqfw-q4vr
  • mermaid (npm) Vendor— Affected before 10.9.6 Fixed in 10.9.6 Patch available GHSA-ghcm-xqfw-q4vr

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:mermaid_project:mermaid:*:*:*:*:*:*:*:*——mermaid-js
  • cpe:2.3:a:mermaid_project:mermaid:*:*:*:*:*:*:*:* Versions — — ·mermaid-js

Remediation

  • Fix · CNA mermaid (mermaid-js) Fixed in 11.15.0, 10.9.6
  • Fix · GHSA-ghcm-xqfw-q4vr mermaid (npm) Fixed in 11.15.0 Advisory →
  • Fix · GHSA-ghcm-xqfw-q4vr mermaid (npm) Fixed in 10.9.6 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Build of Podman DesktopAffectedNo fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-41149
  2. 2026-10-03 Alias added: GHSA-ghcm-xqfw-q4vr

References

Advisory 1

Other 7

  • TI-2026-29778 Mermaid Gantt Charts are vulnerable to an Infinite Loop DoS CVSS 4.0MEDIUM 5.3
  • TI-2025-34615 Mermaid improperly sanitizes of sequence diagram labels leading to XSS CVSS 4.0MEDIUM 5.3
  • TI-2026-50057 Mermaid Architecture diagrams are vulnerable to prototype pollution CVSS 4.0MEDIUM 6.5
  • TI-2022-13152 Arbitrary `CSS` injection into the generated graph affecting the container HTML in mermaid.js CVSS 3.1MEDIUM 6.1
  • TI-2024-25762 Cross-site Scripting in ZenUML CVSS 3.1MEDIUM 5.4
  • TI-2025-34614 Mermaid does not properly sanitize architecture diagram iconText leading to XSS CVSS 4.0MEDIUM 5.1
See all 14 →

Sources

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