How severe is CVE-2026-27125?

CVE-2026-27125 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-27125 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27125?

CVE-2026-27125 affects Svelte. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27125?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-27125 have an EU (EUVD) identifier?

Yes. CVE-2026-27125 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7765.

When was CVE-2026-27125 published?

CVE-2026-27125 was published on 2026-02-20 and last updated on 2026-06-17.

CVE-2026-27125

CVE-2026-27125 is a medium-severity vulnerability in Svelte with a CVSS 3.x base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-915.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v4: 5.3
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-7765
Weakness: CWE-915
Affected product: Svelte
Published: 2026-02-20
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-27125?: 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.
How severe is CVE-2026-27125?: CVE-2026-27125 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-27125 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27125?: CVE-2026-27125 affects Svelte. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27125?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-27125 have an EU (EUVD) identifier?: Yes. CVE-2026-27125 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7765.
When was CVE-2026-27125 published?: CVE-2026-27125 was published on 2026-02-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:svelte:svelte:*:*:*:*:*:node.js:*:*

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