SSRF in Axllent Mailpit
CVE-2026-23845
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.004 (36.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: -0.000
Affected products
- Axllent Mailpit — versions < 1.28.3
Weakness classification (CWE)
References
- github.com/axllent/mailpit/security/advisories/GHSA-6jxm-fv7w-rw5j (Exploit, Vendor Advisory)
- github.com/axllent/mailpit/commit/1679a0aba592ebc8487a996d37fea8318c984dfe (Patch)
- github.com/axllent/mailpit/releases/tag/v1.28.3 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-23845?
- CVE-2026-23845 is a medium-severity vulnerability in Axllent Mailpit, classified under Server-Side Request Forgery (SSRF). CVSS score: 5.8/10. Published 2026-01-19.
- How severe is CVE-2026-23845?
- Medium severity. CVSS v3 base score is 5.8 out of 10.