FreeMail before 5.3.2 Authorization Bypass via /api/create Mailbox Claiming

Summary

FreeMail before 5.3.2 contains an authorization bypass vulnerability that allows authenticated users to claim another user's existing mailbox via the POST /api/create endpoint. Attackers who know a victim's address can become co-owners through assignMailboxToUser to read messages and verification codes, set forwarding, and delete mail.

Remediation

1. Inventory every idinging FreeMail deployment, including staging.
2. Upgrade idinging FreeMail to 5.3.2.
3. Confirm the running version after the upgrade.

References

• Patchhttps://github.com/idinging/freemail/commit/62ed3afdbb4de90a135c12de928e586caf01b5a1
• Advisoryhttps://www.vulncheck.com/advisories/freemail-before-5.3.2-authorization-bypass-via-api-create-mailbox-claiming
• Referencehttps://github.com/idinging/freemail
• Referencehttps://github.com/idinging/freemail/blob/a95c1710e7eeb9f2c74a49ef962f4f43a36695b3/src/db/users.js#L137-L163
• Referencehttps://github.com/idinging/freemail/issues/73
• Referencehttps://github.com/idinging/freemail/releases/tag/v5.3.2