XSS in Astro
CVE-2025-65019
Astro is a web framework. Prior to version 5.15.9, when using Astro's Cloudflare adapter (@astrojs/cloudflare) with output: 'server', the image optimization endpoint (/_image) contains a critical vulnerability in the isRemoteAllowed() function that unconditionally allows data: protocol URLs. This enables Cross-Site Scripting (XSS) attacks through malicious SVG payloads, bypassing domain restrictions and Content Security Policy protections. This issue has been patched in version 5.15.9.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (16.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Astro
- Withastro Astro — versions < 5.15.9
Weakness classification (CWE)
References
- github.com/withastro/astro/security/advisories/GHSA-fvmw-cj7j-j39q (Exploit, Third Party Advisory)
- github.com/withastro/astro/commit/9e9c528191b6f5e06db9daf6ad26b8f68016e533 (Patch)
Frequently asked questions
- What is CVE-2025-65019?
- CVE-2025-65019 is a medium-severity vulnerability in Astro, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2025-11-19.
- How severe is CVE-2025-65019?
- Medium severity. CVSS v3 base score is 5.4 out of 10.