Svelte
CVE-2025-15265
MEDIUM
GHSA-6738-r8g5-qwp3
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS 6.1 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: Required. Exploitable via remote/network. Public exploit/POC available. |
| Exploit ScenarioDerived | A remote attacker could exploit this vulnerability to compromise the affected system. |
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Alert meAnalysisAIv1 – Mar 12, 2026
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. [CVSS 6.1 MEDIUM]
RemediationAI
Monitor vendor advisories for a patch. Implement output encoding and Content Security Policy headers. Restrict network access to the affected service where possible.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in npm
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-79 (Cross-site Scripting (XSS)). Affects Svelte. 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.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
3DescriptionCVE.org
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.
Executive ViewAI
CVE-2025-15265 presents moderate security risk, a cross-site scripting vulnerability rated CVSS 6.1. Attackers could inject scripts to steal sessions or perform actions as authenticated users. Proof-of-concept code is publicly available. Organizations should apply vendor updates when available and monitor for exploitation.
Apply vendor patch. If patching is delayed: implement CSP headers, enable HttpOnly cookies, deploy WAF XSS rules.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
Affected Products (CPE)CVE.org
SvelteKit is a web development framework. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no
SvelteKit is a web development kit. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authe
svelte performance oriented web framework. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable,
The package svelte before 3.49.0 are vulnerable to Cross-site Scripting (XSS) due to improper input sanitization and to
SvelteKit 2.19.0-2.49.4 has SSRF/DoS affecting applications with prerendered routes. Can be exploited to make the server
The SvelteKit framework offers developers an option to create simple REST APIs. Rated high severity (CVSS 8.8), this vul
The unofficial Svelte extension before 104.8.0 for Visual Studio Code allows attackers to execute arbitrary code via a c
In devalue v5.6.3, `devalue.parse` and `devalue.unflatten` were susceptible to prototype pollution via maliciously craft
SvelteKit versions 2.49.0 through 2.49.4 are vulnerable to denial-of-service attacks through the experimental form remot
Denial of service in Svelte devalue library versions 5.1.0 through 5.6.1 allows remote attackers to exhaust CPU and memo
Denial of service in Svelte devalue versions 5.3.0 through 5.6.1 allows remote attackers to exhaust CPU and memory resou
Svelte versions prior to 5.51.5 improperly enumerate prototype chain properties during server-side rendering attribute s
Exploit-DB