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Message-ID: <580b8d25-4cea-4f45-9b83-1f4e0ca12194@oracle.com>
Date: Fri, 17 Jul 2026 13:08:23 -0700
From: Alan Coopersmith <alan.coopersmith@...cle.com>
To: oss-security@...ts.openwall.com
Subject: Cyrus IMAP 3.12.3 fixed 9 CVEs
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.3.html
lists these security fixes in the release notes for the 3.12.3 release:
> * CVE-2026-47084 LOCALDELETE bypassed ACL checks
>
> An authenticated but non-admin user could invoke the admin-only LOCALDELETE
> IMAP command and delete mailboxes for which they had no permissions.
>
> Reported by: Michael Lynch (mtlynch.io)
>
> * CVE-2026-47086 GENURLAUTH issued tokens bypassing ACLs
>
> Any authenticated user could mint a URLAUTH token (via the GENURLAUTH
> command) for any mailbox they could name, even without read access on it.
> This would allow reading mail from mailboxes despite having no granted
> permissions.
>
> Reported by: Matthew Horsfall
>
> * CVE-2026-47087 URLAUTH does not honor revoked authorizer access
>
> A URLAUTH URL minted while the authorizer had access continued to work after
> that access was revoked.
>
> Reported by: Matthew Horsfall
>
> * CVE-2026-47081 XAPPLEPUSHSERVICE folder existence oracle and push hijack
>
> An authenticated IMAP user could probe for the existence of arbitrary
> mailboxes on other users' accounts via the XAPPLEPUSHSERVICE command and
> then create Apple Push Notification Service notifications for new mail in
> those mailboxes to their own APNS device. This did not leak any data about
> the content of mailboxes. Instead, a "mailbox has changed" notice would be
> pushed when the mailbox modseq changed.
>
> Reported by Matthew Horsfall.
>
> * CVE-2026-47089 LISTRIGHTS not limited to users with admin access
>
> An authenticated user could call IMAP LISTRIGHTS against any mailbox they
> could name and learn what principals had what access to it. (This action
> should have been restricted to users with admin access on the target
> mailbox.)
>
> Reported by: Matthew Horsfall
>
> * CVE-2026-47085 URLAUTH token forgery via missing mboxkey
>
> If an attacker knew a folder name on the victim's account for which the
> victim had never issued an auth URL, they could forge a working URLAUTH token
> by computing HMAC-SHA1 with a predictable key, allowing them read access to
> the mailbox.
>
> URLAUTH is an obscure feature, meaning that the odds of any user actually
> being susceptible to this attack are very low. We are unaware of any clients
> using URLAUTH.
>
> Reported by: Matthew Horsfall
>
> * CVE-2026-47083 ESEARCH cross-user content oracle
>
> Using the ESEARCH command, an authenticated IMAP user could enumerate folder
> names under any account they could name. Search would return UIDs of
> messages matching search, creating a content oracle without allowing
> arbitrary reads of the target's content.
>
> Reported by: Michael Lynch (mtlynch.io)
>
> * CVE-2026-47088 Heap exposure in nested MIME comment parsing
>
> An authenticated IMAP user could specially craft an email containing an RFC
> 822 comment ending with a backslash. When parsing the message, the server
> would read past the message end in memory and read into the heap, returning
> the read content to the user.
>
> Reported by: Michael Lynch (mtlynch.io).
>
> * CVE-2026-47082 Vacation "fcc" skips destination-mailbox ACL
>
> A user whose vacation Sieve script used :fcc (to save a copy of the sent
> message) could deliver vacation auto-reply copies into any mailbox the script
> could name, regardless of whether the script owner had insert permissions on
> the destination mailbox.
>
> Reported by: Michael Lynch (mtlynch.io)
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