These two are sold to the same buyer by overlapping vendors and they answer different questions. Patch management applies updates and proves they landed. Vulnerability management finds weaknesses, including ones no patch exists for, and ranks them by how much they matter to you. A team that buys the second expecting the first ends up with a very expensive list, and a team that buys the first expecting the second discovers the gap during an incident.
What each one actually produces
A patch tool produces a fleet state: these machines are current, these are behind, this one has failed three times and needs a look. Its unit of work is an update and its success measure is coverage. A vulnerability tool produces a ranked list of findings: this version of this library has this weakness with this severity, exposed this way on these hosts. Its unit of work is a finding and its success measure is risk reduced. The overlap is real, because most findings resolve to an update, and it is not complete. Vulnerability management also surfaces misconfigurations, weak settings, unsupported software and issues with no patch available, and none of those has a button a patch tool can press.
Which one you need, and in what order
For most MSPs and small internal teams the order is patch first. The great majority of what a vulnerability scan will tell you on an unpatched fleet is that the fleet is unpatched, and paying to be told that at scale is a poor use of a budget. Get patching working, including third-party applications, and the finding count falls dramatically. Vulnerability management earns its place after that, when the remaining findings are the ones patching cannot reach, or when a client or a framework requires scanning specifically. That last case is common and is a legitimate reason to buy in the other order, but it is worth knowing that is what you are doing.
What an insurer or an auditor is usually asking for
Cyber insurance questionnaires and client security reviews mostly ask about patching, in a specific way: how quickly critical patches are applied, across what proportion of the fleet, and can you evidence it. That is a patch management report, and if the reason for the purchase is a questionnaire then the report is the product and should be evaluated before the price is discussed. Where a framework does ask for vulnerability scanning it usually says so by name, so read the requirement rather than the vendor's interpretation of it. Vendors in this market are fluent at presenting whichever product they sell as the answer to whichever question you have.
Questions people ask about patch management vs vulnerability management
What is the difference between patch management and vulnerability management?
Patching applies updates and proves coverage. Vulnerability management finds and ranks weaknesses, including misconfigurations and issues with no patch available, and measures risk reduced rather than coverage.
Do I need both?
Eventually. For most teams the order is patch first, because on an unpatched fleet a vulnerability scan mostly reports that the fleet is unpatched, which is an expensive way to learn it.
Which one does cyber insurance ask about?
Usually patching, and specifically how fast critical patches are applied across what proportion of the fleet, with evidence. That is a patch report, so evaluate the report before the price.
Can one product do both?
Several vendors sell both and integrate them, which is convenient. Check that the vulnerability half is a real scanner rather than a rebadged patch-status report, because those are frequently presented alike.