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Medium 5.3Published Feb 20, 2026

CVE-2026-27125Svelte SSR attribute spreading includes inherited properties from prototype chain

Updated under an hour ago ()

Does this affect you?

It affects sveltejs svelte and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
5.3 MEDIUM (v4.0, CNA)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
Weakness (CWE)
CWE-915
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
Feb 25, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
sveltejs svelte
sveltejs:svelte (from the name)
before 5.51.5
CNA record
svelte svelte
svelte:svelte
before 5.51.5
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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