Mailpit: WebSocket origin check bypass via percent-encoded path (regression of CVE-2026-22689)

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-67448
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-20 22:17:56 UTC
Updated2026-08-21 12:16:30 UTC
DescriptionMailpit 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

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

EPSS: 0.001460000 probability, percentile 0.044190000 (date 2026-08-21)

Problem Types: CWE-177 | CWE-200 | CWE-346 | CWE-177 CWE-177: Improper Handling of URL Encoding (Hex Encoding) | CWE-200 CWE-200: Exposure of Sensitive Information to an Unauthorized Actor | CWE-346 CWE-346: Origin Validation Error

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Axllent Mailpit affected >= 1.29.0, < 1.30.6 Not specified

References

ReferenceSourceLinkTags
github.com/axllent/mailpit/commit/fbe5e006c3f1682b819df58b4a932d7a84920be9 [email protected] github.com
github.com/axllent/mailpit/security/advisories/GHSA-8r62-w5wh-fc5m [email protected] github.com
github.com/axllent/mailpit/releases/tag/v1.30.6 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
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