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VulnerabilityPublished

CVE-2026-41149: mermaid · Code Injection

Affects mermaidSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium : upgrade to 11.15.0 or 10.9.6 when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 4.0 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 34% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 11.15.0, 10.9.6
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade mermaid and mermaid-js/mermaid to 11.15.0 or 10.9.6.

Affected software

ProductAffectedFixed in
mermaid-jsmermaidAffected
  • >=11.0.0-alpha.1 <11.15.0
Fixed in
  • 11.15.0
mermaid-jsmermaidAffected
  • <10.9.6
Fixed in
  • 10.9.6
npmmermaid-js/mermaidpkg:npm/mermaid-js/mermaidOther threatsAffected
  • <10.9.6
  • >=11.0.0 <11.15.0
Fixed in
  • 10.9.6
  • 11.15.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in mermaid versions 10.9.6 and 11.15.0. Users should upgrade to these or later versions to remediate the vulnerability. If immediate upgrading is not feasible, setting the configuration option "securityLevel" to "sandbox" provides a temporary workaround by rendering diagrams in a sandboxed iframe, preventing the injection issue.

Description

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>.

References

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