CVE-2026-67448: CWE-177: Improper Handling of URL Encoding (Hex Encoding) in axllent mailpit
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.
CVE-2026-67448: CWE-177: Improper Handling of URL Encoding (Hex Encoding) in axllent mailpit
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.
CVSS v3.1
Score 6.5medium
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-29T15:07:24.992Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a877790acd9273b492c5fcb
Added to database: 08/20/2026, 21:54:24 UTC
Last updated: 08/20/2026, 21:54:24 UTC
Views: 1
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