CVE-2026-86730 Craft CMS 5.0.0-RC1 before 5.10.12 Behavior Injection RCE
Authenticated Craft CMS users can inject Yii2 behaviors via field layouts to achieve remote code execution.
- 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-2026-86730?
CVE-2026-86730 is a high-severity code injection vulnerability in craftcms cms, published on 8 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Craft CMS versions before 5.10.12 fail to properly cleanse string-typed field-layout elements, allowing authenticated control-panel users to inject Yii2 behavior attachments and event handlers. Attackers can post field-layout tab elements as JSON strings to bypass cleanse validation, then trigger arbitrary object instantiation and code execution through Craft::createObject().
Weakness: CWE-94
Which versions are affected by CVE-2026-86730?
How do I fix CVE-2026-86730?
No fix has been published for CVE-2026-86730 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-2026-86730 being exploited?
There is no known exploitation of CVE-2026-86730 in the wild and no public exploit code.
Sources
Also known as GHSA-j4wp-xfvq-c8f7, GHSA-qj4v-m29p-fj4m.