Svelte 5.46.0 – Hydratable Key Script-Breakout XSS (SSR)_CVE-2025-15265

5.3 / 10

MEDIUM

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

Description

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.

Basic Information

ID CVE-2025-15265

Source Fluid Attacks

Published Jan 15, 2026 at 19:59

Modified Jan 15, 2026 at 20:28

Affected Product

Vendor Svelte

Product Svelte

Version 5.46.0

Affected Versions Svelte Svelte 5.46.0

CWE Classification

CWE-79

References

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    "published": "2026-01-15T19:59:41.683Z",
    "modified": "2026-01-15T20:28:16.479Z",
    "type": "cve",
    "title": "Svelte 5.46.0  - Hydratable Key Script-Breakout XSS (SSR)",
    "source": "Fluid Attacks",
    "references": "https://fluidattacks.com/advisories/lydian\nhttps://github.com/sveltejs/svelte/security/advisories/GHSA-6738-r8g5-qwp3\nhttps://fluidattacks.com/advisories/lydian",
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