CVE - Mitigation Options

Problem reported by kevind - 1/11/2026 at 8:20 PM

Submitted

Saw on a website regarding this particular CVE, it recommended:

Disable file upload functionality if not actively used.
Implement WAF rules to block suspicious file uploads

Our users never need to send attachments, upload files, or use the File Storage area. Is there a way to disable upload functionality on older builds? Thanks.

8 Replies

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kevind Replied

1/15/2026 at 8:06 PM

What if you create a firewall rule that only allows trusted IPs to access the server using a browser. Anyone outside the organization would not be able to access webmail via browser. Does this help mitigate this vulnerability?

Just trying to identify steps to block these attacks on older builds until they can be upgraded.

Reto Replied

1/16/2026 at 12:59 AM

The CVE fixed in last weeks release is using the /api/upload endpoint. You could block access by usign the request filter feature of IIS if really don't need any uploads (attachments, ics uploads, notes import, ...).

But for the security fixes in the release from yesterday you would need to wait for CVE going public and for some no CVE might get published.

Limiting the http/https requests to certain IPs would at least reduce the risk until you can upgrade.

kevind Replied

1/19/2026 at 7:22 AM

@Reto, OK, thanks for the reply!

J. LaDow Replied

1/19/2026 at 8:36 AM

@kevind sent a DM not sure if you got it.

MailEnable survivor / convert --

kevind Replied

1/19/2026 at 9:47 AM

@J., yes got it. Will check out your suggestions.

Thanks!

JohnC Replied

1/20/2026 at 10:15 PM

"Disable file upload functionality if not actively used."

How is this done (where is this setting)?

Reto Replied

1/21/2026 at 12:42 AM

There is no such setting. You could disable the SmarterMail File Storage, but the CVE affects upload for mail attachements, notes or calendar imports and these you can't disable with a setting.

JohnC Replied

1/21/2026 at 8:31 AM

I am a single-user system, so would restricting access to the smwebmail IIS site (by IP or network) fully mitigate this vulnerability? (because that solution would be perfectly acceptable for my use case).

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