sveltejs/svelte · Security
Svelte SSR attribute spreading includes inherited properties from prototype chain
- GHSA ID
- GHSA-crpf-4hrx-3jrp
- CVE ID
- CVE-2026-27125
- Severity
- medium
- Published
- Updated
- CVSS v4
- 5.3 · CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N
Description
In server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected.
CWEs
- CWE-915 · Improperly Controlled Modification of Dynamically-Determined Object Attributes
References
- https://github.com/sveltejs/svelte/security/advisories/GHSA-crpf-4hrx-3jrp ↗
- https://github.com/sveltejs/svelte/commit/73098bb26c6f06e7fd1b0746d817d2c5ee90755f ↗
- https://github.com/sveltejs/svelte/releases/tag/[email protected] ↗
- https://nvd.nist.gov/vuln/detail/CVE-2026-27125 ↗
- https://github.com/advisories/GHSA-crpf-4hrx-3jrp ↗