{"id":"CVE-2026-27902","aliases":["EUVD-2026-8800","GHSA-qgvg-pr8v-6rr3"],"status":"published","title":"Svelte Vulnerable to XSS via HTML Comment Injection in SSR Error Boundary Hydration Markers","description":"Svelte performance oriented web framework. Prior to version 5.53.5, errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`. Version 5.53.5 fixes the issue.","severity":{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00272,"percentile":0.19644,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2026-02-26T00:58:54Z","modified":"2026-10-28T02:30:22Z","fixes":[{"ecosystem":"npm","package":"svelte","fixed_in":["5.53.5"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"svelte","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.53.0"},{"fixed":"5.53.5"}]}]},{"source":"osv","ecosystem":"npm","package":"svelte","ranges":[{"type":"SEMVER","events":[{"introduced":"5.53.0"},{"fixed":"5.53.5"}]}]}],"products":[{"vendor":"svelte","product":"svelte"},{"vendor":"sveltejs","product":"svelte"}],"references":[{"url":"https://github.com/sveltejs/svelte/security/advisories/GHSA-qgvg-pr8v-6rr3","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://github.com/sveltejs/svelte/commit/0298e979371bb583855c9810db79a70a551d22b9","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://github.com/sveltejs/svelte/releases/tag/svelte%405.53.5","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27902","tags":["advisory"]},{"url":"https://github.com/sveltejs/svelte/releases/tag/svelte@5.53.5","tags":["web"]},{"url":"https://github.com/advisories/GHSA-qgvg-pr8v-6rr3"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27902.json","tags":["advisory"]},{"url":"https://github.com/sveltejs/svelte","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-27902","title":"Svelte Vulnerable to XSS via HTML Comment Injection in SSR Error Boundary Hydration Markers","description":"Svelte performance oriented web framework. Prior to version 5.53.5, errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`. Version 5.53.5 fixes the issue.","status":"published","published":"2026-02-26T00:58:54.604Z","modified":"2026-02-26T18:51:39.142Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/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-2026-8800","description":"Svelte performance oriented web framework. Prior to version 5.53.5, errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`. Version 5.53.5 fixes the issue.","status":"published","published":"2026-02-26T00:58:54Z","modified":"2026-02-26T18:51:39Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N","level":"medium"}],"updated_at":"2026-11-02T19:48:16.381292Z"}],"ghsa":[{"id":"GHSA-qgvg-pr8v-6rr3","title":"Svelte: XSS via HTML Comment Injection in SSR Error Boundary Hydration Markers","description":"Errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`.","status":"published","published":"2026-02-26T22:25:45Z","modified":"2026-02-26T22:25:47Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:39:27.949248Z"}],"nvd":[{"id":"CVE-2026-27902","description":"Svelte performance oriented web framework. Prior to version 5.53.5, errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`. Version 5.53.5 fixes the issue.","status":"published","published":"2026-02-26T02:16:21.17Z","modified":"2026-06-17T10:27:51.073Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/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:N/UI:R/S:U/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:07.027269Z"}],"osv":[{"id":"CVE-2026-27902","title":"Svelte Vulnerable to XSS via HTML Comment Injection in SSR Error Boundary Hydration Markers","description":"Svelte performance oriented web framework. Prior to version 5.53.5, errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`. Version 5.53.5 fixes the issue.","status":"published","published":"2026-02-26T00:58:54.604Z","modified":"2026-10-28T02:30:22.982256417Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:00.180685Z"},{"id":"GHSA-qgvg-pr8v-6rr3","title":"Svelte: XSS via HTML Comment Injection in SSR Error Boundary Hydration Markers","description":"Errors from `transformError` were not correctly escaped prior to being embedded in the HTML output, causing potential HTML injection and XSS if attacker-controlled content is returned from `transformError`.","status":"published","published":"2026-02-26T22:25:45Z","modified":"2026-02-26T22:37:20.605129Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:54.40888Z"}]}}