GitHub Advisoryadvisory · npm
GHSA-crpf-4hrx-3jrp Svelte SSR attribute spreading includes inherited properties from prototype chain
MEDIUM
Official page ↗
- Aliases
- CVE-2026-27125
- Ecosystem
- npm
- Packages
- svelte
- Severity
- Moderate
- CVSS vector
- 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
- Weaknesses
- CWE-915
- Reviewed
- 2026-02-19
Affected packages
• npm svelte: < 5.51.5 → fixed in 5.51.5
Description
In server-side rendering, attribute spreading on elements (e.g. ``) 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.
Related
Alias · CVE (1)
- CVE-2026-27125 svelte performance oriented web framework. vulnerability
Weakness · CWE (1)
- CWE-915 Improperly Controlled Modification of Dynamically-Determined Object Attributes weakness
References
- https://github.com/sveltejs/svelte/security/advisories/GHSA-crpf-4hrx-3jrp web
- https://nvd.nist.gov/vuln/detail/CVE-2026-27125 advisory
- https://github.com/sveltejs/svelte/commit/73098bb26c6f06e7fd1b0746d817d2c5ee90755f web
- https://github.com/sveltejs/svelte package
- https://github.com/sveltejs/svelte/releases/tag/[email protected] web