CVE-2026-71438
LOW
INFO
Priority: 0.01
BB Relevance:
15/100
Published: 2026-08-06
Modified: 2026-10-24
First seen: 2026-10-29
Status: active
Attack Surface
Low Complexity
CVSS Vector Breakdown
AV:
Local
AC:
Low
PR:
High
UI:
Active
S:
X
AT:
Present
VC:
None
VI:
Low
VA:
Low
Description
Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Prior to 10.9.8 and 11.16.1, Mermaid's configuration setters (mermaid.initialize, mermaidAPI.setConfig, and mermaidAPI.updateSiteConfig) merge caller-supplied configuration into Mermaid's internal config using the assignWithDepth deep-merge helper, which is vulnerable to prototype pollution. This is only exploitable if an application forwards untrusted data directly into one of these configuration entry points, which is outside their documented usage; diagram-supplied configuration (e.g. %%{init: {}}%% or YAML frontmatter) is not affected. This issue is fixed in versions 10.9.8 and 11.16.1.