CVE-2026-27125

Severity CVSS v4.0:

MEDIUM

Type:

Unavailable / Other

Publication date:

20/02/2026

Last modified:

23/02/2026

Description

svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. ) enumerates inherited properties from the object&#39;s prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte&#39;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.

Impact

Vector 4.0

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 CVSS v4.0 Severity and Metrics:

Base Score: 5.30 MEDIUM
Vector: 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

Attack Vector (AV): Network
Attack Complexity (AC): High
Attack Requirements (AT): Present
Privileges Required (PR): Low
User Interaction (UI): None
Confidentiality (VC): Low
Integrity (VI): Low
Availability (VA): None
Confidentiality (SC): High
Integrity (SI): High
Availability (SA): None

Base Score 4.0

5.30

Severity 4.0

MEDIUM

Vector 3.x

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N CVSS v3.1 Severity and Metrics:

Base Score: 6.80 MEDIUM
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): None