Medium severity · published Jan 15, 2026
CVE-2025-15265
Svelte 5.46.0 - Hydratable Key Script-Breakout XSS (SSR)
6.1
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 28% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SV
Svelte · Svelte
5.46.0 before 5.46.3 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-15265
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-15265
Exploit
https://fluidattacks.com/advisories/lydian
Third Party Advisory
https://github.com/sveltejs/svelte/security/advisories/GHSA-6738-r8g5-qwp3
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