The forms feature in Drupal allows you to inject properties through an unintentional effect of the "Renderable Arrays" feature.
A Malicious user can inject a payload into a vulnerable AJAX form which can achieve remote code execution if they can successfully POST to a vulnerable form endpoint. This exploit is very simple, and scriptable payloads are available on public exploit databases. If any of your public servers are vulnerable to this exploit, automated exploit systems will likely attempt to gain access.
For more information, see the following research.
Vulnerability Fixed in: 7.58, 8.3.9, 8.4.6, 8.5.1
Stay on top of the real risk of open source at any time.
Avoid false positives and get sophisticated upgrade guidance based on risk, compatibility and popularity.
More on Continuous ProtectionDetect and defend against known-vulnerabilities at runtime. The only SCA to do so.
The quickest way to respond to an imminent threat like log4j with CVE-2021-44228.
More on Run-time ProtectionCodeGreen is an early-warning defence for your in-house development and integrates directly into GitHub and BitBucket
More on BitBucket and Github apps