CVE-2026-27129
MEDIUM
GHSA-v2gc-rm6g-wrw9
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Lifecycle Timeline
4Description
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.
Analysis
Craft CMS versions 4.5.0 through 4.16.18 and 5.0.0 through 5.8.22 contain an SSRF bypass in GraphQL Asset mutations where IPv6-only hostnames bypass the security blocklist, allowing authenticated users with GraphQL asset editing permissions to perform server-side request forgery attacks. Public exploit code exists for this vulnerability, which is a regression of a previously patched SSRF issue. …
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Remediation
Within 30 days: Identify affected systems running versions 4.5.0-RC1 and apply vendor patches as part of regular patch cycle. Vendor patch is available.
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External POC / Exploit Code
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