What’s Vulnerable › Vulnerabilities

CVE-2026-79990: GQL entry mutation `siteId` bypasses schema site scope, enabling cross-site content read/write/delete

• Severity: high (CVSS 8.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-02 · updated 2026-09-03
• Weakness: CWE-639

Description

Craft CMS GraphQL entry mutation resolvers (saveEntry, deleteEntry) read siteIddirectly from$argumentswithout passing throughArgumentManagerprepareArguments(), which is the function that enforces site-scope filtering via array_intersect against the GraphQL schema’s allowed sites. The query path (ElementResolverprepareElementQuery) correctly calls prepareArguments()`, so queries to unauthorized sites return empty. But mutations bypass this entirely — an attacker with a token scoped to Site A can create, modify, or delete entries in Site B by passing siteId in the mutations argument.

Affected products

• craftcms cms: from 5.0.0-RC1 before 5.10.11 — fixed in 5.10.11

How to fix

Upgrade to a fixed version: craftcms cms 5.10.11. Check the vendor advisory for mitigations.

References

• https://github.com/craftcms/cms
• https://github.com/craftcms/cms/releases/tag/5.10.11
• https://github.com/craftcms/cms/security/advisories/GHSA-3wcr-p33w-528f
• https://www.hckrt.com/hacktivity/HCKRT-XEQKMX

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