{"id":"CVE-2026-42599","aliases":["CLSA-2026-1784077486","CLSA-2026-1784769502","CLSA-2026-1784769535","CLSA-2026-1784769620","CLSA-2026-1786361581","EUVD-2026-35703","GHSA-pr6f-5x2q-rwfp"],"status":"published","title":"Cross-site scripting via spread attributes in Svelte SSR","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.","severity":{"version":"4.0","score":5.1,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00205,"percentile":0.10577,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2026-05-14T20:19:42Z","modified":"2026-10-28T02:30:48Z","fixes":[{"ecosystem":"npm","package":"svelte","fixed_in":["5.55.7"],"sources":["ghsa","osv"]},{"ecosystem":"TuxCare:npm","package":"svelte","fixed_in":["4.2.20-tuxcare.2","2.16.1-tuxcare.2","1.64.1-tuxcare.2","0.3.0-tuxcare.2"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.55.6"},{"fixed":"5.55.7"}]}]},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.2.20-tuxcare.0"},{"fixed":"4.2.20-tuxcare.2"}]}],"versions":["4.2.20","4.2.20-tuxcare.1"]},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.16.1-tuxcare.0"},{"fixed":"2.16.1-tuxcare.2"}]}],"versions":["2.16.1","2.16.1-tuxcare.1"]},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.64.1-tuxcare.0"},{"fixed":"1.64.1-tuxcare.2"}]}],"versions":["1.64.1","1.64.1-tuxcare.1"]},{"source":"osv","ecosystem":"TuxCare:npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.3.0-tuxcare.0"},{"fixed":"0.3.0-tuxcare.2"}]}],"versions":["0.3.0","0.3.0-tuxcare.1"]},{"source":"osv","ecosystem":"npm","package":"svelte","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.55.7"}]}]}],"products":[{"vendor":"svelte","product":"svelte"},{"vendor":"sveltejs","product":"svelte"}],"references":[{"url":"https://github.com/sveltejs/svelte/security/advisories/GHSA-pr6f-5x2q-rwfp","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://github.com/sveltejs/svelte/releases/tag/svelte%405.55.7","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27121","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42599","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-pr6f-5x2q-rwfp"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42599.json","tags":["advisory"]},{"url":"https://github.com/sveltejs/svelte","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-42599","title":"Cross-site scripting via spread attributes in Svelte SSR","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.","status":"published","published":"2026-06-09T16:22:46.987Z","modified":"2026-06-09T18:39:04.806Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T13:40:23.731501Z"}],"euvd":[{"id":"EUVD-2026-35703","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.","status":"published","published":"2026-06-09T16:22:46Z","modified":"2026-06-09T18:39:04Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium"}],"updated_at":"2026-11-02T18:20:45.803611Z"}],"ghsa":[{"id":"GHSA-pr6f-5x2q-rwfp","title":"Svelte SSR vulnerable to cross-site scripting via spread attributes","description":"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.\n\nThis is similar to but different from [CVE-2026-27121](https://nvd.nist.gov/vuln/detail/CVE-2026-27121).","status":"published","published":"2026-05-14T20:19:42Z","modified":"2026-06-09T18:41:33Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:40:24.856614Z"}],"nvd":[{"id":"CVE-2026-42599","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.","status":"published","published":"2026-06-09T17:17:07.55Z","modified":"2026-07-23T08:10:00.137Z","cvss":[{"version":"4.0","score":5.1,"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/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":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:23.109705Z"}],"osv":[{"id":"CVE-2026-42599","title":"Cross-site scripting via spread attributes in Svelte SSR","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.","status":"published","published":"2026-06-09T16:22:46.987Z","modified":"2026-10-28T02:30:48.518832613Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:04.117819Z"},{"id":"GHSA-pr6f-5x2q-rwfp","title":"Svelte SSR vulnerable to cross-site scripting via spread attributes","description":"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.\n\nThis is similar to but different from [CVE-2026-27121](https://nvd.nist.gov/vuln/detail/CVE-2026-27121).","status":"published","published":"2026-05-14T20:19:42Z","modified":"2026-06-09T18:45:27.163431236Z","cvss":[{"version":"4.0","score":5.1,"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","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:53.700556Z"},{"id":"CLSA-2026-1784077486","title":"TuxCare security update for svelte (1 CVE)","description":"TuxCare rebuilt svelte to address 1 CVE. Fixed in 4.2.20-tuxcare.2.","status":"published","published":"2026-08-04T14:52:44Z","modified":"2026-10-15T09:47:36.201025553Z","updated_at":"2026-11-02T15:43:46.151924Z"},{"id":"CLSA-2026-1784769502","title":"TuxCare security update for svelte (1 CVE)","description":"TuxCare rebuilt svelte to address 1 CVE. Fixed in 2.16.1-tuxcare.2.","status":"published","published":"2026-08-04T14:52:47Z","modified":"2026-10-15T09:47:54.374706608Z","updated_at":"2026-11-02T15:43:46.482572Z"},{"id":"CLSA-2026-1784769535","title":"TuxCare security update for svelte (1 CVE)","description":"TuxCare rebuilt svelte to address 1 CVE. Fixed in 1.64.1-tuxcare.2.","status":"published","published":"2026-08-04T14:52:47Z","modified":"2026-10-15T09:47:36.913337007Z","updated_at":"2026-11-02T15:43:46.482572Z"},{"id":"CLSA-2026-1784769620","title":"TuxCare security update for svelte (1 CVE)","description":"TuxCare rebuilt svelte to address 1 CVE. Fixed in 0.3.0-tuxcare.2.","status":"published","published":"2026-08-04T14:52:48Z","modified":"2026-10-15T09:47:36.679787361Z","updated_at":"2026-11-02T15:43:46.482572Z"},{"id":"CLSA-2026-1786361581","title":"TuxCare security update for jsonwebtoken (2 CVEs)","description":"TuxCare rebuilt jsonwebtoken to address 2 CVEs. Fixed in 0.3.0-tuxcare.2.","status":"withdrawn","published":"2026-08-10T11:33:01Z","modified":"2026-10-26T13:21:31Z","updated_at":"2026-11-02T15:43:46.850893Z"}]}}