CVE-2026-27122
Svelte SSR does not validate dynamic element tag names in `<svelte:element>`
EPSS 0.01%
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.
How to fix CVE-2026-27122
To remediate CVE-2026-27122, upgrade the affected package to a fixed version below.
- npm/svelte—upgrade to 5.51.5 or later
Is CVE-2026-27122 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 5.51.5
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N |