CVE-2026-23829

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. 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 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.

5.3 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References
Link Resource
https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534 Patch
https://github.com/axllent/mailpit/releases/tag/v1.28.3 Product Release Notes
https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c Exploit Third Party Advisory Mitigation
Configurations

Configuration 1 (hide)

cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*
History

23 Feb 2026, 17:29

Type Values Removed Values Added
CPE cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*
First Time Axllent mailpit
Axllent
References () https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534 - () https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534 - Patch
References () https://github.com/axllent/mailpit/releases/tag/v1.28.3 - () https://github.com/axllent/mailpit/releases/tag/v1.28.3 - Product, Release Notes
References () https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c - () https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c - Exploit, Third Party Advisory, Mitigation

19 Jan 2026, 19:16

Type Values Removed Values Added
Summary (en) Mailpit is an email testing tool and API for developers. Prior to version 1.28. 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. (en) 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.

19 Jan 2026, 00:15

Type Values Removed Values Added
New CVE
Information

Published : 2026-01-19 00:15

Updated : 2026-02-23 17:29

NVD link : CVE-2026-23829

Mitre link : CVE-2026-23829

CVE.ORG link : CVE-2026-23829

JSON object : View

Products Affected

axllent

  • mailpit
CWE
CWE-93

Improper Neutralization of CRLF Sequences ('CRLF Injection')

CWE-150

Improper Neutralization of Escape, Meta, or Control Sequences