{"id":"CVE-2026-27121","aliases":["CLSA-2026-1775953999","CLSA-2026-1776040402","CLSA-2026-1776126838","CLSA-2026-1776213244","CLSA-2026-1776213252","EUVD-2026-7521","GHSA-f7gr-6p89-r883"],"status":"published","title":"Svelte affected by cross-site scripting via spread attributes in Svelte SSR","description":"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.","severity":{"version":"4.0","score":5.1,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0022,"percentile":0.12644,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2026-02-19T15:18:33Z","modified":"2026-10-28T02:30:44Z","fixes":[{"ecosystem":"npm","package":"svelte","fixed_in":["5.51.5"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.51.4"},{"fixed":"5.51.5"}]}]},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.2.20-tuxcare.0"},{"fixed":"4.2.20-tuxcare.1"}]}],"versions":["4.2.20"],"bundled":4},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.59.2-tuxcare.0"},{"fixed":"3.59.2-tuxcare.1"}]}],"versions":["3.59.2"],"bundled":5},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.16.1-tuxcare.0"},{"fixed":"2.16.1-tuxcare.1"}]}],"versions":["2.16.1"],"bundled":6},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.64.1-tuxcare.0"},{"fixed":"1.64.1-tuxcare.1"}]}],"versions":["1.64.1"],"bundled":6},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.3.0-tuxcare.0"},{"fixed":"0.3.0-tuxcare.1"}]}],"versions":["0.3.0"],"bundled":6},{"source":"osv","ecosystem":"npm","package":"svelte","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.51.5"}]}]}],"products":[{"vendor":"svelte","product":"svelte"},{"vendor":"sveltejs","product":"svelte"}],"references":[{"url":"https://github.com/sveltejs/svelte/security/advisories/GHSA-f7gr-6p89-r883","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27121","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-f7gr-6p89-r883"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27121.json","tags":["advisory"]},{"url":"https://github.com/sveltejs/svelte","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-27121","title":"Svelte affected by cross-site scripting via spread attributes in Svelte SSR","description":"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.","status":"published","published":"2026-02-20T22:27:36.103Z","modified":"2026-02-23T19:34:18.15Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:19:49.199185Z"}],"euvd":[{"id":"EUVD-2026-7521","description":"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.","status":"published","published":"2026-02-20T22:27:36Z","modified":"2026-02-23T19:34:18Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium"}],"updated_at":"2026-11-02T19:48:32.158773Z"}],"ghsa":[{"id":"GHSA-f7gr-6p89-r883","title":"Svelte affected by cross-site scripting via spread attributes in Svelte SSR","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.","status":"published","published":"2026-02-19T15:18:33Z","modified":"2026-02-23T22:23:06Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:39:26.881079Z"}],"nvd":[{"id":"CVE-2026-27121","description":"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.","status":"published","published":"2026-02-20T23:16:02.503Z","modified":"2026-06-17T10:26:42.29Z","cvss":[{"version":"4.0","score":5.1,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:06.63895Z"}],"osv":[{"id":"CVE-2026-27121","title":"Svelte affected by cross-site scripting via spread attributes in Svelte SSR","description":"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.","status":"published","published":"2026-02-20T22:27:36.103Z","modified":"2026-10-28T02:30:44.602800653Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:44:59.80315Z"},{"id":"GHSA-f7gr-6p89-r883","title":"Svelte affected by cross-site scripting via spread attributes in Svelte SSR","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.","status":"published","published":"2026-02-19T15:18:33Z","modified":"2026-09-10T03:50:34.76848017Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:46.006631Z"},{"id":"CLSA-2026-1775953999","title":"TuxCare security update for svelte (4 CVEs)","description":"TuxCare rebuilt svelte to address 4 CVEs. Fixed in 4.2.20-tuxcare.1.","status":"published","published":"2026-08-04T14:52:24Z","modified":"2026-10-15T09:46:36.148671239Z","updated_at":"2026-11-02T15:43:44.009773Z"},{"id":"CLSA-2026-1776040402","title":"TuxCare security update for svelte (5 CVEs)","description":"TuxCare rebuilt svelte to address 5 CVEs. Fixed in 3.59.2-tuxcare.1.","status":"published","published":"2026-08-04T14:52:24Z","modified":"2026-10-15T09:46:35.699918221Z","updated_at":"2026-11-02T15:43:44.009773Z"},{"id":"CLSA-2026-1776126838","title":"TuxCare security update for svelte (6 CVEs)","description":"TuxCare rebuilt svelte to address 6 CVEs. Fixed in 2.16.1-tuxcare.1.","status":"published","published":"2026-08-04T14:52:25Z","modified":"2026-10-15T09:47:49.780187973Z","updated_at":"2026-11-02T15:43:44.009773Z"},{"id":"CLSA-2026-1776213244","title":"TuxCare security update for svelte (6 CVEs)","description":"TuxCare rebuilt svelte to address 6 CVEs. Fixed in 1.64.1-tuxcare.1.","status":"published","published":"2026-08-04T14:52:25Z","modified":"2026-10-15T09:47:49.789990366Z","updated_at":"2026-11-02T15:43:44.009773Z"},{"id":"CLSA-2026-1776213252","title":"TuxCare security update for svelte (6 CVEs)","description":"TuxCare rebuilt svelte to address 6 CVEs. Fixed in 0.3.0-tuxcare.1.","status":"published","published":"2026-08-04T14:52:25Z","modified":"2026-10-15T09:47:49.842946726Z","updated_at":"2026-11-02T15:43:44.009773Z"}]}}