Email disclosure via permissive WebSocket origin check
Published Jan 10, 2026 · Updated Jan 10, 2026
Cross-site WebSocket hijacking in Axllent Mailpit before 1.28.2 allows remote attackers to read message data through a victim's browser. In server/websockets/client.go, CheckOrigin returns true for every request, so the upgrader accepts cross-origin connections to /api/events. Exploitation requires a developer with Mailpit running to visit attacker-controlled content; the socket exposes email contents, headers, and server statistics in real time.
Summary
What happened
Cross-site WebSocket hijacking in Axllent Mailpit before 1.28.2 allows remote attackers to read message data through a victim's browser. In server/websockets/client.go, CheckOrigin returns true for every request, so the upgrader accepts cross-origin connections to /api/events. Exploitation requires a developer with Mailpit running to visit attacker-controlled content; the socket exposes email contents, headers, and server statistics in real time.
The record
- CVE
- CVE-2026-22689
- Published
- Jan 10, 2026
- Updated
- Jan 10, 2026
- Vendor
- Axllent
- Product
- Mailpit
- Classifications
- CWE-1385, T1114.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 10, 2026CVE publishedPublication date reported by the CVE source.
- Jan 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.28.2
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
- Cross-origin WebSocket hijacking proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo