Description
An unauthenticated server-side request forgery (SSRF) vulnerability in the Thumbnail via-uri endpoint of Halo CMS 2.21 allows a remote attacker to cause the server to issue HTTP requests to attacker-controlled URLs, including internal addresses. The endpoint performs a server-side GET to a user-supplied URI without adequate allow/blocklist validation and returns a 307 redirect that can disclose internal URLs in the Location header.
References1
Metrics
- CVSS 3.1
-
5.8
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N - EPSS — exploit probability
- 0% percentile: 22 · as of 10 November 2026
- CWE
- CWE-918
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.