Medium severity · published Feb 24, 2026
CVE-2026-27129
Cloud Metadata SSRF Protection Bypass via IPv6 Resolution
6.5
CVSS
0.5%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 40% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CM
cms · craftcms
>= 4.5.0-RC1, < 4.16.19; >= 5.0.0-RC1, < 5.8.23 · source: vendor
CC
Craft Cms · Craftcms
3.5.0 before 4.16.19; 5.0.1 before 5.8.23; 5.0.0; 5.0.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27129
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27129
Patch
https://github.com/craftcms/cms/commit/2825388b4f32fb1c9bd709027a1a1fd192d709a3
Exploit
https://github.com/craftcms/cms/security/advisories/GHSA-v2gc-rm6g-wrw9
Not Applicable
https://github.com/craftcms/cms/security/advisories/GHSA-x27p-wfqw-hfcc
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