{"cve":"CVE-2026-42599","nvd":{"published":"2026-06-09T17:17:07.550","modified":"2026-07-23T08:10:00.137","status":"Analyzed","description":"Svelte is a performance oriented web framework. Prior to version 5.55.7, 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. Note that this vulnerability only triggers if the user's browser has JavaScript enabled but Svelte's hydration mechanism does not reach the vulnerable element before the event fires. This issue has been patched in version 5.55.7.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N","score":5.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://github.com/sveltejs/svelte/releases/tag/svelte%405.55.7","https://github.com/sveltejs/svelte/security/advisories/GHSA-pr6f-5x2q-rwfp"],"products":["svelte:svelte"],"source":"nvd","synced_at":"2026-10-19T22:38:48.522727527+00:00"},"epss":{"cve":"CVE-2026-42599","score":0.00205,"percentile":0.10543,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-pr6f-5x2q-rwfp","url":"https://osv.dev/vulnerability/GHSA-pr6f-5x2q-rwfp","summary":"Svelte SSR vulnerable to cross-site scripting via spread attributes","modified":"2026-06-09T18:45:27.163431236Z","packages":[{"ecosystem":"npm","name":"svelte","purl":"pkg:npm/svelte","ranges":["<5.55.7"],"fixed":["5.55.7"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}