PT-2026-3406 · Mailpit · Mailpit
Omarkurt
·
Published
2026-01-18
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Updated
2026-03-13
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CVE-2026-23829
CVSS v3.1
5.3
Medium
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Name of the Vulnerable Software and Affected Versions
Mailpit versions prior to 1.28
Description
Mailpit, an email testing tool and API for developers, has a header injection issue in its SMTP server. This is due to a flawed regular expression used to validate
RCPT TO and MAIL FROM addresses, failing to exclude carriage return characters (r) and newline characters ( ) within a character class. An attacker can inject arbitrary SMTP headers or corrupt existing ones by including these characters in the email address. The insufficient filtering of control characters allows for the manipulation of SMTP headers.Recommendations
Update to version 1.28 or later.
Exploit
Fix
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Related Identifiers
Affected Products
Mailpit