CVE-2026-92589: Craft CMS 5.0.0 before 5.10.13 Broken Access Control via nested-elements/reorder

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-16 · updated 2026-09-22
Weakness: CWE-862

Description

Craft CMS 5.0.0 through 5.10.12 (fixed in 5.10.13) contains a broken access control flaw in the nested-elements reorder endpoint. When an authenticated control panel user with viewEntries and viewPeerEntries (but without savePeerEntries) opens another author's entry in read-only mode, Craft unconditionally grants that session a `manageNestedElements::<ownerId>::field:<handle>` authorization flag for the entry's Matrix/Address fields. Unlike the corresponding delete endpoint, actions/nested-elements/reorder trusts this session flag alone and never rechecks the caller's save permission for the owner element. As a result, a view-only user can POST to actions/nested-elements/reorder using the ownerElementType, ownerId, ownerSiteId, attribute, elementIds, and offset parameters present in the read-only page source and rewrite the sort order of Matrix blocks or Addresses belonging to content they are explicitly denied save access to.

Affected products

craftcms cms: from 5.0.0 before 5.10.13 — fixed in 5.10.13

How to fix

Upgrade to a fixed version: craftcms cms 5.10.13. Check the vendor advisory for mitigations.

References

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