CVE-2025-15265

Severity CVSS v4.0:

MEDIUM

Type:

CWE-79 Cross-Site Scripting (XSS)

Publication date:

15/01/2026

Last modified:

23/01/2026

Description

An SSR XSS exists in async hydration when attacker‑controlled keys are passed to hydratable. The key is embedded inside a block without HTML‑safe escaping, allowing to terminate the script and inject arbitrary JavaScript. This enables remote script execution in users&#39; browsers, with potential for session theft and account compromise.<br /> This issue affects Svelte: from 5.46.0 before 5.46.3.

Impact

Vector 4.0

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 CVSS v4.0 Severity and Metrics:

Base Score: 5.30 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

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): Passsive
Confidentiality (VC): None
Integrity (VI): None
Availability (VA): None
Confidentiality (SC): Low
Integrity (SI): Low
Availability (SA): None

Base Score 4.0

5.30

Severity 4.0

MEDIUM

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 6.10 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Changed
Confidentiality (C): Low
Integrity (I): Low
Availability (A): None