Vulnerability library
Security checkFebruary 23, 2026

Svelte SSR does not validate dynamic element tag names in `<svelte:element>`

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Medium severitynpmsvelte

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Description

When using <svelte:element this={tag}> in server-side rendering, the provided tag name is not validated or sanitized before being emitted into the HTML output. If the tag string contains unexpected characters, it can result in HTML injection in the SSR output. Client-side rendering is not affected.

Recommendation

Update the svelte package to the latest compatible version. Followings are version details:

  • Affected version(s): <= 5.51.4
  • Patched version(s): 5.51.5

References

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See something that needs correcting? Let us knowUpdated February 23, 2026