🛡️ CVE-2026-23829
🟡 CVSS 5.3 — Medium ✅ No Known Exploit CWE-150 NVD
5.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate `RCPT TO` and `MAIL FROM` addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (`\r`) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude `\r` and `\n` when used inside a character class. Version 1.28.3 fixes this issue.

Details

Severity Medium
CVSS Score 5.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CWE CWE-150
Public Exploit ✅ No
Source NVD
Published 2026-01-20
Updated 2026-06-15
Modified 2026-02-03

Affected Packages

Software From version Fixed in
github.com/axllent/mailpit — —
mailpit — 1.28.3

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