GitHub Advisoryadvisory · npm

GHSA-f7gr-6p89-r883 Svelte affected by cross-site scripting via spread attributes in Svelte SSR

MEDIUM Published 2026-02-19 Modified 2026-02-23 Official page ↗
Aliases
CVE-2026-27121
Ecosystem
npm
Packages
svelte
Severity
Moderate
CVSS vector
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
Weaknesses
CWE-79
Reviewed
2026-02-19

Affected packages

• npm svelte: < 5.51.5 → fixed in 5.51.5

Description

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.

Related

Alias · CVE (1)

  • CVE-2026-27121 svelte performance oriented web framework. vulnerability

Weakness · CWE (1)

  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness

References