Medium severity · published Aug 19, 2025
CVE-2025-55303
Unauthorized third-party images in Astro’s _image endpoint
6.1
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 50% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AS
astro · withastro
>= 5.0.0-alpha.0, < 5.13.2; < 4.16.18 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-55303
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-55303
Patch
https://github.com/withastro/astro/commit/4d16de7f95db5d1ec1ce88610d2a95e606e83820
Exploit
https://github.com/withastro/astro/security/advisories/GHSA-xf8x-j4p2-f749
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