CVE-2026-23845

Severity CVSS v4.0:

Pending analysis

Type:

CWE-918 Server-Side Request Forgery (SSRF)

Publication date:

19/01/2026

Last modified:

19/01/2026

Description

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 `` tags to inline them for testing. Version 1.28.3 fixes the issue.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.80 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): Low
Integrity (I): None
Availability (A): None

Base Score 3.x

5.80

Severity 3.x

MEDIUM

CVE-2026-23845

Description

Impact

References to Advisories, Solutions, and Tools