CVE-2026-109308 Craft CMS 4.0.0 before 4.18.7 and 5.0.0 before 5.10.14 RCE via actionCacheUpdates Behavior Injection
Authenticated Craft CMS users with update permissions can execute arbitrary code via behavior injection in the cache updates action.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-109308?
CVE-2026-109308 is a high-severity code injection vulnerability in craftcms cms, published on 12 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Craft CMS 4.0.0 before 4.18.7 and 5.0.0 before 5.10.14 passes the raw 'updates' request parameter in AppController::actionCacheUpdates to UpdatesModel without Component::cleanseConfig(), allowing behavior and event-handler injection. Authenticated control panel users with the performUpdates permission or Updates-utility access can supply 'as' or 'on' keys, such as an AttributeTypecastBehavior gadget, to execute arbitrary code.
Weakness: CWE-94
Which versions are affected by CVE-2026-109308?
How do I fix CVE-2026-109308?
No fix has been published for CVE-2026-109308 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-109308 being exploited?
There is no known exploitation of CVE-2026-109308 in the wild and no public exploit code.
Sources
Also known as GHSA-5m2g-hhqr-84pc, GHSA-r8mr-vm79-xxh4.