CVE-2026-27125

Description

svelte performance oriented web framework. Prior to 5.51.5, 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. This vulnerability is fixed in 5.51.5.

Weakness classification

• security-advisories@github.com: CWE-915

Primary references

• security-advisories@github.com — Patch
• security-advisories@github.com — Product, Release Notes
• security-advisories@github.com — Vendor Advisory