CVE-2026-50279
Craft CMS is a content management system (CMS). IN versions 5.0.0-RC1 and above prior to 5.9.21, theEntriesController::actionSaveEntry() performs entry-edit permission checks before request-controlled author changes are applied to the model, allowing for authorship spoofing. The subsequent author mutation path accepts attacker-supplied authors / author parameters and allows the change when the current user is one of the old authors. Because the controller does not re-run authorization after mutating the author list, a low-privileged user can reassign an entry’s authorship to another user without holding the dedicated peer-author-change permission. This issue has been fixed in version 5.9.21.
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Severity metrics
CVSS 4.0 : 7.6 HIGH
Vector: AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.