8.8High
CVE-2026-86732
Craft CMS versions before 5.10.12 contain a remote code execution vulnerability in the element-index endpoint that allows authenticated content editors to instantiate arbitrary classes through the criteria parameter. Attackers can inject a malicious class via criteria[withTransforms][0][class] that reaches ImageTransforms::normalizeTransform(), then use a PHP gadget chain with yii\rbac\PhpManager to execute code by pointing itemFile to a request log containing PHP payload in the User-Agent header.
What this means for your business
- An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.5% chance of attack attempts being seen in the next 30 days, ranking above 41% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 8.8 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- CVSS v4
- 8.7
- Weakness
- CWE-94
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-08
- Last modified
- 2026-09-10
- Sources
- NVD