Medium severity · published Feb 20, 2026
CVE-2026-27122
Svelte SSR does not validate dynamic element tag names in `<svelte:element>`
5.4
CVSS
0.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SV
svelte · sveltejs
< 5.51.5 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27122
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27122
Vendor Advisory
https://github.com/sveltejs/svelte/security/advisories/GHSA-m56q-vw4c-c2cp
More from svelte
7.5
CVE-2026-42567
Svelte: ReDoS in `<svelte:element>` Tag Validation
6.8
CVE-2026-27125
Svelte SSR attribute spreading includes inherited properties from prototype chain
6.1
CVE-2026-42599
Cross-site scripting via spread attributes in Svelte SSR
6.1
CVE-2026-42573
Svelte: XSS via DOM Clobbering of Internal Framework State
6.1
CVE-2026-27901
Svelte vulnerable to XSS during SSR with contenteditable `bind:innerText` and `bind:textContent`