Craft CMS allows attackers to inject a URL into the saveAsset GraphQL mutation. The application validates the target hostname and resolved IP against a blacklist, but the underlying Guzzle HTTP client follows redirects by default. An attacker can thus place a redirect that points to cloud metadata or internal IP addresses, bypassing all SSRF safeguards and enabling remote server side request forgery, data exfiltration, or privilege escalation.

All Craft CMS releases from 4.0.0‑RC1 to 4.16.17 and from 5.0.0‑RC1 to 5.8.21 are vulnerable. The issue is fixed in 4.16.18 and 5.8.22.

The CVSS score of 6.9 indicates moderate severity, while the EPSS score below 1% shows a very low probability of exploitation. The vulnerability is not listed in the CISA KEV catalog. Attackers would need control over a GraphQL request to the application; once someone runs the malicious mutation, the server’s HTTP client will follow the redirect and access the target internal resource.