CVE-2026-40878 Scanner.
Mailcow < 2026-03b - Href Link Injection
Free and read-only. Scan only sites you own or are allowed to test.
What This Check Does.
Read-only
It only asks your site for public pages, the way a browser would. Nothing is changed, uploaded or stored.
Up to 2 requests
A small, fixed number of requests, so the check is quick and will not load your site.
Looks for CVE-2026-40878
It looks for the specific sign of this one vulnerability and ends with a clear answer: vulnerable, not vulnerable, or could not be determined.
About CVE-2026-40878. What It Means.
mailcow < 2026-03b reflects raw REQUEST_URI into JavaScript and href links on the login page, allowing attackers to inject parameters that break JS logic and enable phishing.
FAQ
Common Questions.
Mailcow < 2026-03b - Href Link Injection. mailcow < 2026-03b reflects raw REQUEST_URI into JavaScript and href links on the login page, allowing attackers to inject parameters that break JS logic and enable phishing.
Atlas sends up to 2 read-only requests to your site and looks for the specific sign of CVE-2026-40878 in Mailcow Dockerized. Nothing is changed, uploaded or stored on your site.
CVE-2026-40878 is not on the CISA Known Exploited Vulnerabilities list at the time of writing, but it is still worth fixing. Its CVSS score is 3.1.
Yes. The check only reads public pages, the same way a browser or a search engine would. Scan only sites you own or are allowed to test.
It means no sign of CVE-2026-40878 was found by this read-only check. It does not prove the site is free of other weaknesses.
Update Mailcow Dockerized to the latest version from the vendor, or follow the vendor's advice to switch off the affected feature. The vendor links and details are in the CVE-2026-40878 briefing linked on this page.
Scan only sites you own or have written permission to test. A result of Not Vulnerable means this read-only check found no sign of CVE-2026-40878; it is not a guarantee that the site is secure.