CVE-2026-23845
January 19, 2026
Mailpit is an email testing tool and API for developers. Versions prior to 1.28.3 are vulnerable to Server-Side Request Forgery (SSRF) via HTML Check CSS Download. The HTML Check feature ("/api/v1/message/{ID}/html-check") is designed to analyze HTML emails for compatibility. During this process, the "inlineRemoteCSS()" function automatically downloads CSS files from external "<link rel="stylesheet" href="...">" tags to inline them for testing. Version 1.28.3 fixes the issue.
Affected Packages
github.com/axllent/mailpit (GO):
Affected version(s) >=v1.2.6 <v1.28.3Fix Suggestion:
Update to version v1.28.3github.com/axllent/mailpit (GO):
Affected version(s) >=v0.0.0-20220730100312-c6f1c8213b0b <v1.28.3Fix Suggestion:
Update to version v1.28.3Related Resources (5)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
LOW
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.8
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Server-Side Request Forgery (SSRF)
EPSS
Base Score:
0.04
