CVE-2026-27125

low-risk
Published 2026-02-20

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.

Do I need to act?

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0.03% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
6
CVSS 6.8/10 Medium
NETWORK / HIGH complexity

Affected Products (1)

Svelte

Affected Vendors

26
/ 100
low-risk
Severity 21/34 · High
Exploitability 0/34 · Minimal
Exposure 5/34 · Minimal