PublicCVE

CVE-2026-27121

MEDIUM5.1JSON exportCreate alert

Description

svelte performance oriented web framework. Versions of svelte prior to 5.51.5 are vulnerable to cross-site scripting (XSS) during server-side rendering. When using spread syntax to render attributes from untrusted data, event handler properties are included in the rendered HTML output. If an application spreads user-controlled or external data as element attributes, an attacker can inject malicious event handlers that execute in victims' browsers. This vulnerability is fixed in 5.51.5.

CVSS breakdown

CVSS 4.0
Attack Vector
Network
Attack Complexity
High
Attack Requirements
Present
Privileges Required
High
User Interaction
None
Confidentiality (Vulnerable System)
Low
Integrity (Vulnerable System)
None
Availability (Vulnerable System)
None
Confidentiality (Subsequent System)
High
Integrity (Subsequent System)
High
Availability (Subsequent System)
None

Affected products