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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-23829 Detail

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534 GitHub, Inc. Patch 
https://github.com/axllent/mailpit/releases/tag/v1.28.3 GitHub, Inc. Product  Release Notes 
https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c GitHub, Inc. Exploit  Mitigation  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-93 Improper Neutralization of CRLF Sequences ('CRLF Injection') GitHub, Inc.  
CWE-150 Improper Neutralization of Escape, Meta, or Control Sequences GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

5 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-23829
NVD Published Date:
01/18/2026
NVD Last Modified:
06/17/2026
Source:
GitHub, Inc.