CVE-2026-27122
Medium · 5.4CVSS
5.4
EPSS
0.3%
Published
Feb 20, 2026
CISA due date
—
The record
svelte performance oriented web framework. Prior to 5.51.5, 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. This vulnerability is fixed in 5.51.5.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| npm | svelte | 0 | 5.51.5 |
| Chainguard | langfuse-3-worker | 0 | 3.163.0-r0 |
| Chainguard | langfuse-fips-3-worker | 0 | 3.163.0-r0 |
| Wolfi | langfuse-3-worker | 0 | 3.163.0-r0 |
Related vulnerabilities
- GHSA-m56q-vw4c-c2cp Svelte SSR does not validate dynamic element tag names in `` Same vulnerability
- CVE-2026-42567 Svelte is a performance oriented web framework. Also affects svelte
- CVE-2026-42599 Svelte is a performance oriented web framework. Also affects svelte
- CVE-2026-42573 Svelte is a performance oriented web framework. Also affects svelte
- GHSA-f3cj-j4f6-wq85 Svelte: SSR XSS via Insecure Promise Serialization in hydratable Also affects svelte
- GHSA-rcqx-6q8c-2c42 Svelte Vulnerable to XSS via DOM Clobbering of Internal Framework State Also affects svelte
- GHSA-9rmh-mm8f-r9h6 Svelte: ReDoS in `` Tag Validation Also affects svelte
- GHSA-pr6f-5x2q-rwfp Svelte SSR vulnerable to cross-site scripting via spread attributes Also affects svelte