How Does a Mutable Smart Contract Differ Fundamentally from an Immutable One in Terms of Security?

An immutable contract is inherently more secure against code tampering post-deployment because its logic cannot be changed, offering predictability. A mutable contract, while allowing fixes, introduces the risk of a malicious upgrade by the contract owner or governance mechanism, creating a central point of failure.

Security relies heavily on the integrity of the upgrade mechanism and the governance controlling it.