This build strengthens protections against clients that were introduced in v7.4.2 and updates log4j to 2.15.0 to properly patch the issue on the server.
Server owners should direct their players to install patched versions of the Minecraft client, where appropriate. For vanilla players, this is as simple as restarting their vanilla client: see https://www.minecraft.net/en-us/article/important-message--security-vulnerability-java-edition
USERS SHOULD UPDATE TO THIS SERVER VERSION AS SOON AS POSSIBLE
Server owners should download spongevanilla-1.12.2-7.4.3.jar