Vulnerability · Published Aug 20, 2026 · Assigned by GitHub_M
CVE-2026-67448Mailpit: WebSocket origin check bypass via percent-encoded path (regression of CVE-2026-22689)
Medium 6.5
In plain English
A medium-severity information exposure in mailpit from axllent. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Mailpit is an email testing tool and API for developers. From 1.29.0 until 1.30.6, Mailpit's server/server.go origin middleware checks the raw RequestURI for the /api/ prefix while Go's ServeMux routes using the percent-decoded URL path, and server/websockets/client.go configures websocket.Upgrader.CheckOrigin to return true. A malicious website can request /%61pi/events, skip corsOriginAccessControl(), reach the /api/events WebSocket handler, and receive live message IDs, Message-Id values, sender and recipient fields, subjects, tags, and body snippets from an unauthenticated default Mailpit instance after the user visits the site. This is a regression of the earlier WebSocket origin protection and does not affect deployments protected by --ui-auth-file. This issue is fixed in version 1.30.6.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/axllent/mailpit | 1.30.6 | GHSA-8r62-w5wh-fc5m |
| Go | github.com/axllent/mailpit | 1.30.6 | GO-2026-6271 |
Affected products (as reported)
Weakness: CWE-177, CWE-200, CWE-346 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
References
- https://github.com/axllent/mailpit/security/advisories/GHSA-8r62-w5wh-fc5m x_refsource_CONFIRM
- https://github.com/axllent/mailpit/commit/fbe5e006c3f1682b819df58b4a932d7a84920be9 x_refsource_MISC
- https://github.com/axllent/mailpit/releases/tag/v1.30.6 x_refsource_MISC