CVE-2026-27121

MEDIUM

5.4

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.

CVE Details

CVSS v3.1 Score5.4

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredLOW

User InteractionREQUIRED

Published2/20/2026

Last Modified2/23/2026

Sourcenvd

Honeypot Sightings0

Affected Products

svelte:svelte

Weaknesses (CWE)

CWE-79

References

https://github.com/sveltejs/svelte/security/advisories/GHSA-f7gr-6p89-r883(security-advisories@github.com)

IOC Correlations

No correlations recorded

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