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.
CVSS breakdown
CVSS 4.0
Attack Vector
Network
Attack Complexity
High
Attack Requirements
Present
Privileges Required
Low
User Interaction
None
Confidentiality (Vulnerable System)
Low
Integrity (Vulnerable System)
Low
Availability (Vulnerable System)
None
Confidentiality (Subsequent System)
High
Integrity (Subsequent System)
High
Availability (Subsequent System)
None
Affected products
- sveltejs / svelte< 5.51.5 – < 5.51.5