vulnerability / NVI-00015089 / Revision 1
Mermaid allows CSS injection applying to sibling elements of the diagram
GitHub lists this reviewed advisory for mermaid, mermaid. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
mermaid
source listed>= 11.0.0-alpha.1, < 11.16.1
### Summary Mermaid does not fully restrict CSS to the rendered SVG subtree. Although selectors are prefixed with `#mermaid-X`, sibling (`~` and `+`) combinators can still escape the Mermaid container and inject styles to DOM elements adjacent to the diagram ``. **Most users of mermaid would not be affected by this**, as mermaid adds its `` as an only child of it's parent element. However, you may be affected if you manually insert the `` (or other elements) into the DOM yourself. ### Details Mermaid namespaces CSS through with a middleware intended to scope all rules to the diagram's SVG element. CSS nesting expands `& ~ * { ... }` to `#svgId ~ *`, which selects all sibling elements following the SVG in the DOM, outside the diagram boundary. ### Impact An attacker able to supply diagram source to a page (e.g., user-generated content rendered by Mermaid) could inject CSS rules affecting sibling elements to the diagram `` on the host page. This can be used for UI redressing, hiding content, conditional CSS-based probing, or phishing-style visual manipulation. JavaScript execution is not possible via this vector. ### Patches This has been patched in https
mermaid
source listed< 10.9.8
### Summary Mermaid does not fully restrict CSS to the rendered SVG subtree. Although selectors are prefixed with `#mermaid-X`, sibling (`~` and `+`) combinators can still escape the Mermaid container and inject styles to DOM elements adjacent to the diagram ``. **Most users of mermaid would not be affected by this**, as mermaid adds its `` as an only child of it's parent element. However, you may be affected if you manually insert the `` (or other elements) into the DOM yourself. ### Details Mermaid namespaces CSS through with a middleware intended to scope all rules to the diagram's SVG element. CSS nesting expands `& ~ * { ... }` to `#svgId ~ *`, which selects all sibling elements following the SVG in the DOM, outside the diagram boundary. ### Impact An attacker able to supply diagram source to a page (e.g., user-generated content rendered by Mermaid) could inject CSS rules affecting sibling elements to the diagram `` on the host page. This can be used for UI redressing, hiding content, conditional CSS-based probing, or phishing-style visual manipulation. JavaScript execution is not possible via this vector. ### Patches This has been patched in https
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-6x64-9x62-f2gx ↗
GitHub Advisory Database · vendor advisory
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Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.