XSS in Svelte

CVE-2026-27119

svelte performance oriented web framework. From 5.39.3, <=5.51.4, in certain circumstances, the server-side rendering output of an <option> element does not properly escape its content, potentially allowing HTML injection in the SSR output. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (10.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-27119: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-27119?
CVE-2026-27119 is a medium-severity vulnerability in Svelte, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-02-20.
How severe is CVE-2026-27119?
Medium severity. CVSS v3 base score is 5.4 out of 10.