Answer in brief
CVE-2026-71438 records a Low severity (CVSS 2.4) vulnerability in Mermaid configuration APIs allow prototype pollution. The current sources do not mark it as known exploited. The current feed maps mermaid-js/mermaid (generic), mermaid (npm), mermaid (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-71438 records a Low severity (CVSS 2.4) vulnerability in Mermaid configuration APIs allow prototype pollution. The current sources do not mark it as known exploited. The current feed maps mermaid-js/mermaid (generic), mermaid (npm), mermaid (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 2.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps mermaid-js/mermaid (generic), mermaid (npm), mermaid (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| mermaid-js/mermaidgeneric | < 10.9.8 || >= 11.0.0-alpha.1, < 11.16.1 | Not reported |
| mermaidnpm | >=11.0.0-alpha.1,<11.16.1 | 11.16.1 |
| mermaidnpm | <10.9.8 | 10.9.8 |
Published upstream
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.
CVSS is 2.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps mermaid-js/mermaid (generic), mermaid (npm), mermaid (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| mermaid-js/mermaidgeneric | < 10.9.8 || >= 11.0.0-alpha.1, < 11.16.1 | Not reported |
| mermaidnpm | >=11.0.0-alpha.1,<11.16.1 | 11.16.1 |
| mermaidnpm | <10.9.8 | 10.9.8 |
Published upstream
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.