CVE-2021-31855
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations....
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations. 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. With a 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. This occurs in ViewerPrivate::deleteAttachment in messageviewer/src/viewer/viewer_p.cpp.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
6.5
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations. 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. With a 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. This occurs in ViewerPrivate::deleteAttachment in messageviewer/src/viewer/viewer_p.cpp.
- Record
CVE-2021-31855- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - CVSS 2.0
- 4.0 Medium
AV:N/AC:L/Au:S/C:P/I:N/A:N - Weakness
- CWE-312
- Updated
- 2026-11-02
CVE List No score
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations. 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. With a 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. This occurs in ViewerPrivate::deleteAttachment in messageviewer/src/viewer/viewer_p.cpp.
- Record
CVE-2021-31855- Updated
- 2026-11-02
EUVDEUVD-2021-18730 No score
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations. 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. With a 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. This occurs in ViewerPrivate::deleteAttachment in messageviewer/src/viewer/viewer_p.cpp.
- Record
EUVD-2021-18730- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-h76g-vp43-8cw5
6.5
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations....
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations. 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. With a 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. This occurs in ViewerPrivate::deleteAttachment in messageviewer/src/viewer/viewer_p.cpp.
- Record
GHSA-h76g-vp43-8cw5- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-312, CWE-319
- Updated
- 2026-11-02
OSV
6.5
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations. 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. With a 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. This occurs in ViewerPrivate::deleteAttachment in messageviewer/src/viewer/viewer_p.cpp.
- Record
CVE-2021-31855- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-31855
6.5
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations. 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. With a 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. This occurs in ViewerPrivate::deleteAttachment in messageviewer/src/viewer/viewer_p.cpp.
- Record
DEBIAN-CVE-2021-31855- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-31855
6.5
KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations. 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. With a 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. This occurs in ViewerPrivate::deleteAttachment in messageviewer/src/viewer/viewer_p.cpp.
- Record
UBUNTU-CVE-2021-31855- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVMGASA-2021-0208 No score
Updated messagelib packages fix security vulnerability
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.
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 (CVE-2021-31855).
- Record
MGASA-2021-0208- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:11046-1 No score
messagelib-21.08.1-1.2 on GA media
These are all security issues fixed in the messagelib-21.08.1-1.2 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:11046-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
kf5-messagelibDebian:12 |
before 4:20.08.3-5 | 4:20.08.3-5 |
messagelibMageia:7 |
before 19.04.0-1.2.mga7 | 19.04.0-1.2.mga7 |
messagelibMageia:8 |
before 20.12.0-1.1.mga8 | 20.12.0-1.1.mga8 |
kdepim4Ubuntu:18.04:LTS |
All versions, plus listed versions 4:4.14.10-7 |
None known |
kf5-messagelibUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 4:17.04.3-0ubuntu14:17.04.3-0ubuntu24:17.08.3-0ubuntu14:17.08.3-0ubuntu24:17.12.2-0ubuntu34:17.12.3-0ubuntu24:17.12.3-0ubuntu34:17.12.3-0ubuntu3+esm1 |
None known |
kf5-messagelibUbuntu:20.04:LTS |
All versions, plus listed versions 4:19.04.3-0ubuntu14:19.04.3-0ubuntu24:19.12.3-0ubuntu1 |
None known |
kf5-messagelibUbuntu:22.04:LTS |
All versions, plus listed versions 4:21.08.1-0ubuntu14:21.08.3-0ubuntu24:21.11.80-0ubuntu14:21.11.90-0ubuntu14:21.12.0-0ubuntu14:21.12.1-0ubuntu14:21.12.2-0ubuntu14:21.12.3-0ubuntu1 |
None known |
kf5-messagelibUbuntu:24.04:LTS |
All versions, plus listed versions 4:23.08.1-0ubuntu14:23.08.2-0ubuntu14:23.08.3-0ubuntu14:23.08.4-0ubuntu14:23.08.5-0ubuntu14:23.08.5-0ubuntu34:23.08.5-0ubuntu4 |
None known |
messagelibopenSUSE:Tumbleweed From an advisory covering 2 CVEs |
before 21.08.1-1.2 | 21.08.1-1.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-31855 is a medium vulnerability (CVSS 6.5) in Kde Messagelib, published May 7, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.61%, the 49th percentile. Fixed in kf5-messagelib 4:20.08.3-5.