CVE-2026-23829

MEDIUM EPSS 69.9%
Published Jan 19, 20265mo ago · Modified Jun 17, 20261w ago
5.3 CVSS 3.1
Medium
Find Similar
Published Jan 19, 2026 5mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
5.3
Exploitability
3.9
Impact
1.4
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity Low
Availability None

Threat Intelligence

EPSS Exploit Probability
69.9% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 2

CWE-150
CWE-93

Affected Products 1

VendorProductVersionRange
axllentmailpit* <1.28.3

References 3

  • github.com https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534
    Patch
  • github.com https://github.com/axllent/mailpit/releases/tag/v1.28.3
    ProductRelease Notes
  • github.com https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c
    ExploitMitigationThird Party Advisory

Remediation

  • github.com https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534
    Patch