CVE-2026-21859 Details.
Mailpit < 1.28.3 - Server-Side Request Forgery
Atlas does not check this one. Needs an outside server.
To test for this one, the site would have to contact a server outside your network and report back. Atlas does not run checks that need that, so it does not run this one.
About CVE-2026-21859. What It Means.
Mailpit <= 1.28.0 contains a server-side request forgery caused by insufficient validation of internal IP addresses in the /proxy endpoint, letting attackers make requests to internal network resources, exploit requires crafted HTTP GET requests.
Affected Product. What Is Hit.
- Vendor
- axllent
- Product
- Axllent Mailpit
More CVEs In Axllent Mailpit.
FAQ
Common Questions.
Mailpit < 1.28.3 - Server-Side Request Forgery. Mailpit <= 1.28.0 contains a server-side request forgery caused by insufficient validation of internal IP addresses in the /proxy endpoint, letting attackers make requests to internal network resources, exploit requires crafted HTTP GET requests.
No. To test for this one, the site would have to contact a server outside your network and report back. Atlas does not run checks that need that, so it does not run this one. The facts about CVE-2026-21859 are on this page, and you can request a demo to see how Brandefense watches your whole external attack surface.
CVE-2026-21859 is not on the CISA Known Exploited Vulnerabilities list at the time of writing, but it is still worth fixing.
Update Axllent Mailpit to the latest version from the vendor, or follow the vendor's advice to switch off the affected feature. Vendor links are listed on this page when they are known.
This page lists the public facts about CVE-2026-21859. Atlas does not run a check for it, so nothing here says whether a particular site is affected.