CVE-2026-23845

Name: CVE-2026-23845
Creator: NVD / NIST
Published: 2026-01-19T19:16:04.82+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.40%

Last modified Jun 17, 2026

CVE-2026-23845 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.40% chance of exploitation in the next 30 days.

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 `<link rel="stylesheet" href="...">` tags to inline them for testing. Version 1.28.3 fixes the issue.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

0.40%

31.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-918

Affected Software

Vendor	Product	Versions
Axllent	Mailpit	< 1.28.3

References

https://github.com/axllent/mailpit/commit/1679a0aba592ebc8487a996d37fea8318c984dfePatch
https://github.com/axllent/mailpit/releases/tag/v1.28.3Product, Release Notes
https://github.com/axllent/mailpit/security/advisories/GHSA-6jxm-fv7w-rw5jExploit, Vendor Advisory

Timeline

Published: Jan 19, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-23845?

How severe is CVE-2026-23845?

CVE-2026-23845 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.

How do I fix CVE-2026-23845?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-23845?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST