Bypass in SSRF Validation in Craft CMS Affects Various Versions
CVE-2026-27129

5.7MEDIUM

Key Information:

Vendor

Craftcms

Status
Cms
Vendor
CVE Published:
24 February 2026

What is CVE-2026-27129?

Craft CMS, a widely used content management system, has a security flaw in the server-side request forgery (SSRF) validation process within its GraphQL Asset mutation. The issue arises from the use of the gethostbyname() function, which is limited to resolving IPv4 addresses. Consequently, when hostnames possess only AAAA (IPv6) records, the function fails to appropriately handle them, allowing bypassing of critical SSRF protections. The vulnerability is particularly concerning in environments where users have been granted GraphQL schema permissions for editing and creating assets, especially if misconfigured to allow public write access. Users are advised to update to versions 4.16.19 or 5.8.23, which address this severe issue.

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Affected Version(s)

cms >= 4.5.0-RC1, < 4.16.19 < 4.5.0-RC1, 4.16.19

cms >= 5.0.0-RC1, < 5.8.23 < 5.0.0-RC1, 5.8.23

References

https://github.com/craftcms/cms/security/advisories/GHSA-...
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https://github.com/craftcms/cms/security/advisories/GHSA-...
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https://github.com/craftcms/cms/commit/2825388b4f32fb1c9b...
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CVSS V4

Score:
5.7
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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