Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Craftcms | Craft Cms | >= 3.5.0, < 4.16.19 |
Related Weaknesses (CWE)
References
- https://github.com/craftcms/cms/commit/2825388b4f32fb1c9bd709027a1a1fd192d709a3Patch
- https://github.com/craftcms/cms/security/advisories/GHSA-v2gc-rm6g-wrw9ExploitMitigationPatch
- https://github.com/craftcms/cms/security/advisories/GHSA-x27p-wfqw-hfccNot Applicable
FAQ
What is CVE-2026-27129?
CVE-2026-27129 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 ...
How severe is CVE-2026-27129?
CVE-2026-27129 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-27129?
Check the references section above for vendor advisories and patch information. Affected products include: Craftcms Craft Cms.