CVE-2026-27121mediumCWE-79

CVE-2026-27121: medium-severity vulnerability in sveltejs svelte

Svelte affected by cross-site scripting via spread attributes in Svelte SSR

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 5.1epss 0.2%
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:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N
Affected products
sveltejs · svelte
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