CVE-2026-23829

MEDIUM

5.3

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.

CVE Details

CVSS v3.1 Score5.3

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published1/19/2026

Last Modified2/23/2026

Sourcenvd

Honeypot Sightings0

Affected Products

axllent:mailpit

Weaknesses (CWE)

CWE-93CWE-150

References

https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534(security-advisories@github.com)

https://github.com/axllent/mailpit/releases/tag/v1.28.3(security-advisories@github.com)

https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c(security-advisories@github.com)

IOC Correlations

No correlations recorded

This product uses data from the NVD API but is not endorsed or certified by the NVD.