Astro Cloudflare adapter has a Stored Cross Site Scripting vulnerability in /_image endpoint
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-79.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| withastro | astro | before 5.15.9 | 5.15.9 | Patch available | CNA |
| — | astro (npm) | before 5.15.9 | 5.15.9 | Patch available | GHSA-fvmw-cj7j-j39q |
- astro Vendorwithastro Affected before 5.15.9 Fixed in 5.15.9 Patch available CNA
- astro (npm) Vendor— Affected before 5.15.9 Fixed in 5.15.9 Patch available GHSA-fvmw-cj7j-j39q
Remediation
- Fix · CNA astro (withastro) Fixed in 5.15.9
- Fix · GHSA-fvmw-cj7j-j39q astro (npm) Fixed in 5.15.9 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2025-65019
- 2026-10-03 Alias added: GHSA-fvmw-cj7j-j39q
References
More withastro Astro vulnerabilities
- TI-2024-37142 Server source code is exposed to the public if sourcemaps are enabled CVSS 4.0HIGH 7.8
- TI-2025-34958 Unauthorized third-party images in Astro’s _image endpoint CVSS 4.0MEDIUM 6.9
- TI-2025-39915 Server-side request forgery in withastro astro CVSS 3.1MEDIUM 6.5
- TI-2025-38274 Astro's `X-Forwarded-Host` is reflected with no validation CVSS 3.1MEDIUM 6.5
- TI-2026-36915 Astro: Reflected XSS via unescaped slot name CVSS 3.1HIGH 7.1
- TI-2025-40102 Astro is vulnerable to Reflected XSS via the server islands feature CVSS 3.1HIGH 7.1
Sources
- CVE-2025-65019 · CVE Program
- CVE-2025-65019 · NVD
- FIRST EPSS
- GHSA-fvmw-cj7j-j39q · GitHub Advisory Database · CC BY 4.0
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