Dan Walsh writes in detail about how SELinux mitigates recent vulnerabilities in Samba. The referenced vulnerabilities potentially allow remote arbitrary code execution due to coding errors: exactly the kind of thing SELinux was designed to protect against.
It’s notable is that the SELinux memory execution controls are key here, as they are often the cause of problems with third-party software installation vs. SELinux issues. More often than you’d expect, applications and/or libraries will try to do highly questionable things like making areas of the heap executable, which SELinux will typically prevent. This tends to be seen more in closed software, which is also unfortunately harder to fix. In any case, SELinux is usually doing the right thing for you when this happens, as explained by Ulrich Drepper.
Generally, the best solution for software such as this is to fix it and make it safe; not to disable security protections. Ulrich provides example code of how to make such fixes in the referenced article.