PT-2026-20881 · Svelte · Svelte

Elliott-With-The-Longest-Name-On-Github · CVE-2026-27122 · Published 2026-02-19 · Updated 2026-02-20

Positive Technologies (AI Summary)

CVSS v3.1

5.4

Medium

Base vector

AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Name of the Vulnerable Software and Affected Versions Svelte versions prior to 5.51.5

Description A flaw exists in Svelte where, during server-side rendering, the tag name provided to the <svelte:element this={tag}> component is not validated or sanitized before being included in the HTML output. This can lead to HTML injection if the tag string contains malicious characters. Client-side rendering is not impacted by this issue. The vulnerable component is <svelte:element this={tag}>. The vulnerable variable is tag.

Recommendations Update to version 5.51.5 or later.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-27122

GHSA-M56Q-VW4C-C2CP

Affected Products

Svelte

References · 7

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27122.json · Exploit
• https://github.com/sveltejs/svelte/security/advisories/GHSA-m56q-vw4c-c2cp · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-m56q-vw4c-c2cp · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-27122 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-27122 · Security Note
• https://github.com/sveltejs/svelte · Note
• https://twitter.com/CVEnew/status/2024988713919598840 · Twitter Post