As noted here a while ago, the latest wsusscn2.cab can be downloaded from go.microsoft.com/fwlink/?LinkId=76054. Also here, there seems to be an equivalent link go.microsoft.com/fwlink/p/?LinkID=74689.

Is there a Microsoft or third party web service notifying when an updated wsusscn2.cab version is available?

Is there a similar tool/DB for quality updates (not feature)?

The venerable catalog.update.microsoft.com seems a viable alternative, but I don't see an API to query the catalog.


Assuming that you're talking about an automated process, you should be able to do this by querying the Last-Modified HTTP header directly from the download site.

Because the official URL is a redirection, you'll need to process that first.

So a HEAD request to http://go.microsoft.com/fwlink/p/?LinkID=74689 returns

HTTP/1.0 301 Moved Permanently => 
Location => http://download.windowsupdate.com/microsoftupdate/v6/wsusscan/wsusscn2.cab
Server => Kestrel
Request-Context => appId=cid-v1:b47e5e27-bf85-45ba-a97c-0377ce0e5779
X-Response-Cache-Status => True
X-Powered-By => ASP.NET
Content-Length => 0
Expires => Sat, 15 Dec 2018 02:19:15 GMT
Cache-Control => max-age=0, no-cache, no-store
Pragma => no-cache
Date => Sat, 15 Dec 2018 02:19:15 GMT
Connection => close

From the Location field you obtain the download URL, which in this case is http://download.windowsupdate.com/microsoftupdate/v6/wsusscan/wsusscn2.cab from which you get:

HTTP/1.0 200 OK => 
Pragma => no-cache
Content-Type => application/vnd.ms-cab-compressed
Accept-Ranges => bytes
Server => Microsoft-IIS/10.0
X-Powered-By => ASP.NET
Last-Modified => Tue, 11 Dec 2018 11:39:53 GMT
ETag => "80ca583b4691d41:0"
Content-Length => 482287090
Date => Sat, 15 Dec 2018 02:19:46 GMT
Connection => close
X-CID => 2
Cache-Control => max-age=0

When the Last-Modified value changes, a new version of wsusscn2.cab is available. Note that this file is updated infrequently, usually only once a month on Patch Tuesday when new security updates are released, so depending on your scenario it is probably sufficient to check at most a few times a day. There might be occasional false positives, if this is a problem for you you should also check the date on the digital signature of the downloaded file.

If I've misunderstood and you're not talking about an automated process, you can sign up for Microsoft Technical Security Notifications. These notifications won't explicitly tell you when wsusscn2.cab has been updated, but they will tell you when new security updates are available, and that's almost the same thing.

The Security Update Guide also provides an API.

  • +1 Correct, I am interested in automation. Any ideas for quality updates? – antonio Dec 15 '18 at 2:42
  • If I'm remembering the jargon correctly, the "quality updates" are the cumulative security updates released each month. Information about these will be available from the Security Update Guide API (I've never used it myself, but that's what it is for) although I don't know whether there will be anything to distinguish them from any other sort of security update. Non-cumulative security updates are relatively infrequent though - I guess a few a year - so perhaps this won't be a problem. – Harry Johnston Dec 15 '18 at 2:49

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