CVE-2026-27129
Description
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.
How to fix
- craftcms craft_cms4.16.19, 5.8.23 or later
- craftcms/cms5.8.23, 4.16.19 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| craftcms craft_cms | 3.5.0 ≤ v < 4.16.19, 5.0.1 ≤ v < 5.8.23, 5.0.0 | 4.16.19, 5.8.23 |
| craftcms/cmsPackagist | 5.0.0-RC1 ≤ v < 5.8.23, 3.5.0 ≤ v < 4.16.19 | 5.8.23, 4.16.19 |
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