CVE-2026-27129 PUBLISHED

Cloud Metadata SSRF Protection Bypass via IPv6 Resolution

Assigner: GitHub_M
Reserved: 17.02.2026 Published: 24.02.2026 Updated: 24.02.2026

Craft is a content management system (CMS). In versions 4.5.0-RC1 through 4.16.18 and 5.0.0-RC1 through 5.8.22, the SSRF validation in Craft CMS’s GraphQL Asset mutation uses gethostbyname(), which only resolves IPv4 addresses. When a hostname has only AAAA (IPv6) records, the function returns the hostname string itself, causing the blocklist comparison to always fail and completely bypassing SSRF protection. This is a bypass of the security fix for CVE-2025-68437. Exploitation requires GraphQL schema permissions for editing assets in the <VolumeName> volume and creating assets in the <VolumeName> volume. These permissions may be granted to authenticated users with appropriate GraphQL schema access and/or Public Schema (if misconfigured with write permissions). Versions 4.16.19 and 5.8.23 patch the issue.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
CVSS Score: 5.7

Product Status

Vendor craftcms
Product cms
Versions
  • Version >= 4.5.0-RC1, < 4.16.19 is affected
  • Version >= 5.0.0-RC1, < 5.8.23 is affected

References

Problem Types

  • CWE-918: Server-Side Request Forgery (SSRF) CWE