CVE-2025-15265
Svelte 5.46.0 - Hydratable Key Script-Breakout XSS (SSR)
- State
- Published
- Severity
- 5.3 Medium
- Published
- Jan 15, 2026
- Updated
- Jan 15, 2026
- Reserved
- Dec 29, 2025
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.3 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 | Fluid Attacks |
Weaknesses
- CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')
Affected Products
| Product | Versions |
|---|---|
SvelteSvelte |
|
References
- https://fluidattacks.com/advisories/lydianthird-party-advisory
- https://github.com/sveltejs/svelte/security/advisories/GHSA-6738-r8g5-qwp3vendor-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.