CVE-2025-55303

MEDIUMNuclei

Unauthorized third-party images in Astro’s _image endpoint

Title source: CVE List
STIX 2.1 vulnerability

Record summary

CVE-2025-55303 has a selected CVSS score of 6.9 (medium); EIP currently links 1 Nuclei template.

Description

Astro is a web framework for content-driven websites. In versions of astro before 5.13.2 and 4.16.18, the image optimization endpoint in projects deployed with on-demand rendering allows images from unauthorized third-party domains to be served. On-demand rendered sites built with Astro include an /_image endpoint which returns optimized versions of images. A bug in impacted versions of astro allows an attacker to bypass the third-party domain restrictions by using a protocol-relative URL as the image source, e.g. /_image?href=//example.com/image.png. This vulnerability is fixed in 5.13.2 and 4.16.18.

Description source: CVE List

Exploitation context

Known exploitation

VulnCheck KEV
Listed · Feb 12, 2026 · VulnCheck
Reported exploitation
Observed · VulnCheck

Available material

Nuclei templates
1

CISA SSVC decision

ExploitationPoC
AutomatableYes
Technical impactPartial

CISA Coordinator · SSVC 2.0.3 · Evaluated Aug 19, 2025 · Source: CVE List

Affected products and versions

4
ProductSourceVersion range

astro

Browse astro / astro
VulnCheckVersion data not supplied

astro

Browse withastro / astro
CVE List>= 5.0.0-alpha.0, < 5.13.2affected
< 4.16.18affected

@astrojs/node

Browse npm / @astrojs/node
GitHub AdvisoryBefore 9.1.1 · Fixed in 9.1.1affected

astro

Browse npm / astro
GitHub Advisory5.0.0-alpha.0 to < 5.13.2 · Fixed in 5.13.2affected
Before 4.16.19 · Fixed in 4.16.19affected

Nuclei templates

1
ProjectDiscoveryMEDIUMAstro - Unauthorized Third-Party Image AccessCVSS 6.4

Astro < 5.13.2 and < 4.16.18 contains an information disclosure vulnerability caused by improper validation of protocol-relative URLs in the image optimization endpoint, letting attackers serve images from unauthorized third-party domains, exploit requires on-demand rendering deployment.

Impact

Attackers can serve images from unauthorized third-party domains, potentially leading to information disclosure or content spoofing.

Remediation

Update to versions 5.13.2 or 4.16.18 or later.

WeaknessesCWE-79
Authorstheamanrawat
Template tagscvecve2025astrossrfvulnvkev
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
Shodan: http.html:"astro"
https://github.com/advisories/GHSA-xf8x-j4p2-f749 https://nvd.nist.gov/vuln/detail/CVE-2025-55303

Source: ProjectDiscovery

References

4