Astro Cloudflare adapter has a Stored Cross Site Scripting vulnerability in /_image endpoint

published 2025-11-19 11mo ago modified 2026-10-18 22d ago also EUVD-2025-198182 , GHSA-fvmw-cj7j-j39q

cvss: 5.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

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.

Patch / fix

fixed in 2 links 1

npm astro 5.15.9
astro astro 5.15.9

github.com/withastro/astro@9e9c528 commit

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CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 11mo ago (2025-11-19)

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

github.com https://github.com/withastro/astro/security/advisories/GHSA-fvmw-cj7j-j39q referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
GitHub	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
NVD	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	astro	<5.15.9	5.15.9

Affected products

withastro astro

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /withastro/astro/commit/9e9c528191b6f5e06db9daf6ad26b8f68016e533
web, patch
github.com /withastro/astro/security/advisories/GHSA-fvmw-cj7j-j39q
web, exploit, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2025-65019
advisory
github.com /withastro/astro
package

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

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