CVE-2026-27121

CVE-2026-27121 · Svelte affected by cross-site scripting via spread attributes in Svelte SSR

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svelte performance oriented web framework. Versions of svelte prior to 5.51.5 are vulnerable to cross-site scripting (XSS) during server-side rendering. When using spread syntax to render attributes from untrusted data, event handler properties are included in the rendered HTML output. If an application spreads user-controlled or external data as element attributes, an attacker can inject malicious event handlers that execute in victims' browsers. This vulnerability is fixed in 5.51.5.

CVSS 5.1 · Medium · EPSS 0.2% · Fix available

Published

2026-02-20T22:27:36.103Z

Updated

2026-02-23T19:34:18.150Z

Stack: node

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