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                             CERT-Renater

                 Note d'Information No. 2021/VULN252
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DATE                : 30/04/2021

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running KMail, messagelib versions prior to
                                           5.17.1.

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https://kde.org/info/security/advisory-20210429-1.txt
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KDE Project Security Advisory
=============================

Title:          KMail: Deleting attachments can disclose content of
                       encrypted messages
Risk Rating:    Low
CVE:            CVE-2021-31855
Versions:       KMail, messagelib < 5.17.1
Author:         Ingo Klöcker <kloecker@kde.org>
Date:           29 April 2021

Overview
========

Deleting an attachment of a decrypted encrypted message stored on a
remote server (e.g. an IMAP server) causes KMail to upload the decrypted
content of the message to the remote server. This is not easily
noticeable by the user because KMail does not display the decrypted
content.


Impact
======

With a specially crafted message a user could be tricked into decrypting
an encrypted message and then deleting an attachment attached to this
message. If the attacker has access to the messages stored on the email
server, then the attacker could read the decrypted content of the
encrypted message.


Workaround
==========

Do not delete attachments of encrypted messages.


Solution
========

Update to messagelib >= 5.17.1 (when released)

Or apply this patch:
https://commits.kde.org/messagelib/3b5b171e91ce78b966c98b1292a1bcbc8d984799


Credits
=======

Thanks to Ingo Klöcker for reporting and fixing the issue.


=========================================================
+ CERT-RENATER       |    tel : 01-53-94-20-44          +
+ 23/25 Rue Daviel   |    fax : 01-53-94-20-41          +
+ 75013 Paris        |    email:cert@support.renater.fr +
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