Debian alert DLA-4766-1 (cyrus-imapd)

From:
             
 
Xavier Guimard <yadd@debian.org>
To:
             
 
debian-lts-announce@lists.debian.org
Subject:
             
 
[SECURITY] [DLA 4766-1] cyrus-imapd security update
Date:
             
 
Tue, 01 Sep 2026 18:26:37 +0200
Message-ID:
             
 
<20260901162637.5A77F8C00C1@m.xnr.fr>
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Debian LTS Advisory DLA-4766-1                debian-lts@lists.debian.org
https://www.debian.org/lts/security/                       Xavier Guimard
September 01, 2026                            https://wiki.debian.org/LTS
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Package        : cyrus-imapd
Version        : 3.6.1-4+deb12u5
CVE ID         : CVE-2026-47081 CVE-2026-47082 CVE-2026-47084 CVE-2026-47085 
                 CVE-2026-47086 CVE-2026-47087 CVE-2026-47088 CVE-2026-47089

Several vulnerabilities were discovered in cyrus-imapd, a highly scalable
mail store with support for IMAP, JMAP, POP3, CalDAV and CardDAV. Most of
them allow authenticated users to bypass access control lists (ACL) and to
access or modify other users' mailboxes.

CVE-2026-47081

    The XAPPLEPUSHSERVICE command allowed an authenticated user to probe
    for the existence of other users' mailboxes and to hijack their push
    notifications.

CVE-2026-47082

    Delivery of the Sieve vacation "fcc" copy skipped the ACL check on the
    destination mailbox, allowing a user to write messages into a mailbox
    they have no rights on.

CVE-2026-47084

    The LOCALDELETE command bypassed ACL checks, allowing non-admin users
    to delete mailboxes they are not permitted to delete.

CVE-2026-47085

    URLAUTH tokens could be forged because a predictable empty mboxkey was
    accepted, giving unauthorized access to message content.

CVE-2026-47086

    The GENURLAUTH command issued URLAUTH tokens without checking the
    ACL_READ right on the target mailbox.

CVE-2026-47087

    URLAUTH tokens remained valid after the access rights of the user who
    issued them had been revoked.

CVE-2026-47088

    A heap out-of-bounds read was possible when parsing nested MIME
    comments in RFC 822 headers, which may lead to a denial of service.

CVE-2026-47089

    The LISTRIGHTS command was not restricted to users having admin rights
    on the target mailbox, disclosing the ACL of other users' mailboxes.

These issues were fixed upstream in Cyrus IMAP 3.10.3 and have been
backported to the 3.6 branch, which upstream no longer supports.

For Debian 12 bookworm, these problems have been fixed in version
3.6.1-4+deb12u5.

We recommend that you upgrade your cyrus-imapd packages.

For the detailed security status of cyrus-imapd please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/cyrus-imapd

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS
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