sveltejs svelte up to 5.51.4 dynamically-determined object attributes

Summaryinfo

A vulnerability identified as problematic has been detected in sveltejs svelte up to 5.51.4. The affected element is an unknown function. Performing a manipulation results in dynamically-determined object attributes. This vulnerability is known as CVE-2026-27125. Remote exploitation of the attack is possible. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in sveltejs svelte up to 5.51.4. This affects some unknown functionality. The manipulation with an unknown input leads to a dynamically-determined object attributes vulnerability. CWE is classifying the issue as CWE-915. The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-27125 since 02/17/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. Neither technical details nor an exploit are publicly available.

Upgrading to version 5.51.5 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 73098bb26c6f06e7fd1b0746d817d2c5ee90755f is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• sveltejs

Name

• svelte

Version

• 5.51.0
• 5.51.1
• 5.51.2
• 5.51.3
• 5.51.4

License

• open-source

Website

• Product: https://github.com/sveltejs/svelte/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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