CVE-2025-15265CWE-79

Svelte 5.46.0 - Hydratable Key Script-Breakout XSS (SSR)

Medium · published January 15, 2026

CVSS v4.0
5.3
EPSS
0%
Percentile
26.9
In the wild
Unconfirmed
What it is

An SSR XSS exists in async hydration when attacker‑controlled keys are passed to hydratable. The key is embedded inside a <script> block without HTML‑safe escaping, allowing </script> to terminate the script and inject arbitrary JavaScript. This enables remote script execution in users' browsers, with potential for session theft and account compromise.

This issue affects Svelte: from 5.46.0 before 5.46.3.

The record
Technical detail
CVSS v4.0
5.3 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
EPSS
0.00346 · 26.9th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-01-15T19:59Z
EPSS history
Timeline
  • 15 JAN 19:59Z
    Svelte 5.46.0 - Hydratable Key Script-Breakout XSS (SSR)
    cvelistv5