What is CVE-2026-23829?

CVE-2026-23829 is a medium-severity vulnerability in Axllent Mailpit, classified under CRLF Injection. CVSS score: 5.3/10. Published 2026-01-18.

How severe is CVE-2026-23829?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Axllent Mailpit

CVE-2026-23829

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 at…

Vulnerability class: CRLF Injection

EPSS: 0.016 (82.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

Affected products

Axllent Mailpit — versions < 1.28.3

Weakness classification (CWE)

References

https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c (x_refsource_CONFIRM)
https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534 (x_refsource_MISC)
https://github.com/axllent/mailpit/releases/tag/v1.28.3 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-23829?: CVE-2026-23829 is a medium-severity vulnerability in Axllent Mailpit, classified under CRLF Injection. CVSS score: 5.3/10. Published 2026-01-18.
How severe is CVE-2026-23829?: Medium severity. CVSS v3 base score is 5.3 out of 10.