Vulnerability in Axllent Mailpit
CVE-2026-22689
Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim's Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.002 (14.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: -0.000
Affected products
- Axllent Mailpit — versions < 1.28.2
Weakness classification (CWE)
References
- github.com/axllent/mailpit/security/advisories/GHSA-524m-q5m7-79mm (Exploit, Mitigation, Vendor Advisory)
- github.com/axllent/mailpit/commit/6f1f4f34c98989fd873261018fb73830b30aec3f (Patch)
Frequently asked questions
- What is CVE-2026-22689?
- CVE-2026-22689 is a medium-severity vulnerability in Axllent Mailpit, classified under CWE-1385. CVSS score: 6.5/10. Published 2026-01-10.
- How severe is CVE-2026-22689?
- Medium severity. CVSS v3 base score is 6.5 out of 10.