CVE-2025-15265

MEDIUM

Svelte 5.46.0-5.46.2 - Server-Side Rendering Cross-Site Scripting via Async Hydration Key Injection

Title source: llm
STIX 2.1

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.

References (2)

Core 2
Core References
Exploit, Third Party Advisory third-party-advisory
https://fluidattacks.com/advisories/lydian

Scores

CVSS v3 6.1
EPSS 0.0002
EPSS Percentile 4.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-79
Status published
Products (2)
npm/svelte 5.46.0 - 5.46.4npm
svelte/svelte 5.46.0 - 5.46.3
Published Jan 15, 2026
Tracked Since Feb 18, 2026