{"id":"CVE-2026-42567","aliases":["EUVD-2026-35702","GHSA-9rmh-mm8f-r9h6"],"status":"published","title":"Svelte: ReDoS in `\u003csvelte:element\u003e` Tag Validation","description":"Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in \u003csvelte:element this={tag}\u003e\u003c/svelte:element\u003e. This issue has been patched in version 5.55.7.","severity":{"version":"4.0","score":5.9,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00451,"percentile":0.39506,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1333"],"published":"2026-05-14T20:29:05Z","modified":"2026-10-28T02:31:13Z","fixes":[{"ecosystem":"npm","package":"svelte","fixed_in":["5.55.7"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.51.5"},{"last_affected":"5.55.6"},{"fixed":"5.55.7"}]}]},{"source":"osv","ecosystem":"npm","package":"svelte","ranges":[{"type":"SEMVER","events":[{"introduced":"5.51.5"},{"fixed":"5.55.7"}]}]}],"products":[{"vendor":"svelte","product":"svelte"},{"vendor":"sveltejs","product":"svelte"}],"references":[{"url":"https://github.com/sveltejs/svelte/security/advisories/GHSA-9rmh-mm8f-r9h6","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://github.com/sveltejs/svelte/releases/tag/svelte%405.55.7","tags":["x_refsource_MISC","Product","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42567","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-9rmh-mm8f-r9h6"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42567.json","tags":["advisory"]},{"url":"https://github.com/sveltejs/svelte","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-42567","title":"Svelte: ReDoS in `\u003csvelte:element\u003e` Tag Validation","description":"Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in \u003csvelte:element this={tag}\u003e\u003c/svelte:element\u003e. This issue has been patched in version 5.55.7.","status":"published","published":"2026-06-09T16:22:22.703Z","modified":"2026-06-09T18:09:26.356Z","cvss":[{"version":"4.0","score":5.9,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-1333"],"updated_at":"2026-11-02T13:40:35.004553Z"}],"euvd":[{"id":"EUVD-2026-35702","description":"Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in \u003csvelte:element this={tag}\u003e\u003c/svelte:element\u003e. This issue has been patched in version 5.55.7.","status":"published","published":"2026-06-09T16:22:22Z","modified":"2026-06-09T18:09:26Z","cvss":[{"version":"4.0","score":5.9,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T18:20:47.241018Z"}],"ghsa":[{"id":"GHSA-9rmh-mm8f-r9h6","title":"Svelte: ReDoS in `\u003csvelte:element\u003e` Tag Validation","description":"An internal regex in the Svelte runtime can take exponential time to test in `\u003csvelte:element this={tag}\u003e\u003c/svelte:element\u003e`. You are only vulnerable to this if you allow tags of unconstrained length. If your application only allows a predetermined list of tags or trims their length before passing them to `svelte:element`, you are safe.","status":"published","published":"2026-05-14T20:29:05Z","modified":"2026-06-09T18:41:20Z","cvss":[{"version":"4.0","score":5.9,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-1333"],"updated_at":"2026-11-02T14:40:24.856614Z"}],"nvd":[{"id":"CVE-2026-42567","description":"Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in \u003csvelte:element this={tag}\u003e\u003c/svelte:element\u003e. This issue has been patched in version 5.55.7.","status":"published","published":"2026-06-09T17:17:07.1Z","modified":"2026-07-23T08:10:00.137Z","cvss":[{"version":"4.0","score":5.9,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-1333"],"updated_at":"2026-11-02T14:12:23.109705Z"}],"osv":[{"id":"CVE-2026-42567","title":"Svelte: ReDoS in `\u003csvelte:element\u003e` Tag Validation","description":"Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in \u003csvelte:element this={tag}\u003e\u003c/svelte:element\u003e. This issue has been patched in version 5.55.7.","status":"published","published":"2026-06-09T16:22:22.703Z","modified":"2026-10-28T02:31:13.310226747Z","cvss":[{"version":"4.0","score":5.9,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-1333"],"updated_at":"2026-11-02T15:45:04.117819Z"},{"id":"GHSA-9rmh-mm8f-r9h6","title":"Svelte: ReDoS in `\u003csvelte:element\u003e` Tag Validation","description":"An internal regex in the Svelte runtime can take exponential time to test in `\u003csvelte:element this={tag}\u003e\u003c/svelte:element\u003e`. You are only vulnerable to this if you allow tags of unconstrained length. If your application only allows a predetermined list of tags or trims their length before passing them to `svelte:element`, you are safe.","status":"published","published":"2026-05-14T20:29:05Z","modified":"2026-06-09T18:45:23.337407449Z","cvss":[{"version":"4.0","score":5.9,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-1333"],"updated_at":"2026-11-02T15:46:44.225359Z"}]}}