CVE-2026-23829 Details.
Mailpit < 1.28.2 - SMTP CRLF Injection
Atlas does not check this one. Not a plain web check.
This weakness is not found through ordinary web pages. It needs a different kind of connection to the service. Atlas only runs plain web, DNS and TLS checks, so it does not run this one.
About CVE-2026-23829. What It Means.
Mailpit < 1.28 contains a header injection caused by insufficient regex validation of `RCPT TO` and `MAIL FROM` addresses in the SMTP server, letting attackers inject arbitrary SMTP headers, exploit requires crafted email addresses
Affected Product. What Is Hit.
- Vendor
- axllent
- Product
- Axllent Mailpit
More CVEs In Axllent Mailpit.
FAQ
Common Questions.
Mailpit < 1.28.2 - SMTP CRLF Injection. Mailpit < 1.28 contains a header injection caused by insufficient regex validation of `RCPT TO` and `MAIL FROM` addresses in the SMTP server, letting attackers inject arbitrary SMTP headers, exploit requires crafted email addresses
No. This weakness is not found through ordinary web pages. It needs a different kind of connection to the service. Atlas only runs plain web, DNS and TLS checks, so it does not run this one. The facts about CVE-2026-23829 are on this page, and you can request a demo to see how Brandefense watches your whole external attack surface.
CVE-2026-23829 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-2026-23829. Atlas does not run a check for it, so nothing here says whether a particular site is affected.