CVE-2026-27129 Cloud Metadata SSRF Protection Bypass via IPv6 Resolution
Authenticated users with specific GraphQL permissions can bypass SSRF protections via IPv6 resolution to access cloud metadata.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-27129?
CVE-2026-27129 is a medium-severity server-side request forgery vulnerability in Craftcms Craft Cms, published on 24 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-918
Which versions are affected by CVE-2026-27129?
4 open source packages ship an affected version, including craftcms/cms. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
craftcms/cms Packagist | From 3.5.0 | 4.16.19 |
craftcms/cms Packagist | From 3.5.0 | 4.16.19 |
craftcms/cms Packagist | From 5.0.0-RC1 | 5.8.23 |
craftcms/cms Packagist | From 5.0.0-RC1 | 5.8.23 |
Products include Craftcms Craft Cms.
How do I fix CVE-2026-27129?
Upgrade craftcms/cms to a fixed version for your release line: 4.16.19 or 5.8.23.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-27129 being exploited?
There is no known exploitation of CVE-2026-27129 in the wild and no public exploit code.
Other vulnerabilities in Craftcms Craft Cms
Sources
Also known as GHSA-v2gc-rm6g-wrw9.