{"id":"CVE-2026-27121","aliases":["GHSA-f7gr-6p89-r883"],"url":"https://o3.security/vulnerability/CVE-2026-27121","summary":"Svelte affected by cross-site scripting via spread attributes in Svelte SSR","details":"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.","published":"2026-02-20T22:27:36.103Z","modified":"2026-07-15T01:48:57.978742129Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"svelte","fixedVersion":"5.51.5"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27121.json"},{"type":"ADVISORY","url":"https://github.com/sveltejs/svelte/security/advisories/GHSA-f7gr-6p89-r883"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27121"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:48:57.978742129Z"}}