Message disclosure via WebSocket origin bypass
Published Aug 20, 2026 · Updated Aug 20, 2026
Origin validation error in Axllent Mailpit before 1.30.6 allows remote attackers to read message metadata via a crafted WebSocket path. In server/server.go, the CORS middleware keys its /api/ check on raw RequestURI while Go routes on decoded r.URL.Path; requesting /%61pi/events therefore skips corsOriginAccessControl() and still reaches /api/events, and server/websockets/client.go configured websocket.Upgrader.CheckOrigin to accept every origin before the fix. Exploitation requires a default unauthenticated Mailpit instance and user interaction to load a malicious website; deployments protected by --ui-auth-file are not exposed, and the observed disclosure is limited to live message IDs, Message-Id values, sender and recipient fields, subjects, tags, and body snippets.
Summary
What happened
Origin validation error in Axllent Mailpit before 1.30.6 allows remote attackers to read message metadata via a crafted WebSocket path. In server/server.go, the CORS middleware keys its /api/ check on raw RequestURI while Go routes on decoded r.URL.Path; requesting /%61pi/events therefore skips corsOriginAccessControl() and still reaches /api/events, and server/websockets/client.go configured websocket.Upgrader.CheckOrigin to accept every origin before the fix. Exploitation requires a default unauthenticated Mailpit instance and user interaction to load a malicious website; deployments protected by --ui-auth-file are not exposed, and the observed disclosure is limited to live message IDs, Message-Id values, sender and recipient fields, subjects, tags, and body snippets.
The record
- CVE
- CVE-2026-67448
- Published
- Aug 20, 2026
- Updated
- Aug 20, 2026
- Vendor
- Axllent
- Product
- Mailpit
- Classifications
- CWE-346, CWE-177, T1189
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 20, 2026CVE publishedPublication date reported by the CVE source.
- Aug 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 1.29.0, < 1.30.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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