CVE-2022-25875 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in svelte. 2 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for svelte — see the affected versions and patch details below.
Cross-site Scripting (XSS)
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
sveltenpmDescription
The package svelte before 3.49.0 are vulnerable to Cross-site Scripting (XSS) due to improper input sanitization and to improper escape of attributes when using objects during SSR (Server-Side Rendering). Exploiting this vulnerability is possible via objects with a custom toString() function.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | svelte | all versions | 3.49.0npm install svelte@3.49.0 |
Affected Products
sveltesvelteResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for svelte, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update svelte to 3.49.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-25875 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2022-25875 in your dependencies?
Find it across npm, including transitive dependencies.