CVE-2026-27122
MEDIUMsvelte < 5.51.5 - Cross-Site Scripting via Server-Side Rendering Tag Injection
Title source: llmDescription
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.
References (1)
Core 1
Core References
Vendor Advisory x_refsource_confirm
https://github.com/sveltejs/svelte/security/advisories/GHSA-m56q-vw4c-c2cp
Scores
CVSS v3
5.4
EPSS
0.0001
EPSS Percentile
1.4%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-79
Status
published
Products (2)
npm/svelte
0 - 5.51.5npm
svelte/svelte
< 5.51.5
Published
Feb 20, 2026
Tracked Since
Feb 21, 2026