CVE-2026-27902

Svelte Vulnerable to XSS via HTML Comment Injection in SSR Error Boundary Hydration Markers

CVSS 5.3 MEDIUMEPSS 0.2%CWE-79

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.

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

Affected products

sveltejs · svelte

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References

https://github.com/sveltejs/svelte/commit/0298e979371bb583855c9810db79a70a551d22b9 https://github.com/sveltejs/svelte/releases/tag/svelte%405.53.5 https://github.com/sveltejs/svelte/security/advisories/GHSA-qgvg-pr8v-6rr3