Answer in brief
CVE-2026-50159 records a Medium severity (CVSS 5.3) vulnerability in Mermaid allows CSS injection applying to sibling elements of the diagram. 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-2026-50159 records a Medium severity (CVSS 5.3) vulnerability in Mermaid allows CSS injection applying to sibling elements of the diagram. 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 5.3. 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 is vulnerable to CSS injection via sibling combinator selectors generated from diagram-supplied class or id names. An attacker who can supply diagram text can inject arbitrary CSS into the rendered page, potentially altering the appearance or behavior of unrelated page elements. This issue is fixed in versions 10.9.8 and 11.16.1.
Quoted source text, attributed separately from HOL analysis.
CVSS is 5.3. 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 is vulnerable to CSS injection via sibling combinator selectors generated from diagram-supplied class or id names. An attacker who can supply diagram text can inject arbitrary CSS into the rendered page, potentially altering the appearance or behavior of unrelated page elements. This issue is fixed in versions 10.9.8 and 11.16.1.
Quoted source text, attributed separately from HOL analysis.