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Fencer Intel
medium 6.5

CVE-2021-31855 json

KDE Messagelib through 5.17.0 reveals cleartext of encrypted messages in some situations.

published 5y ago modified 4mo ago also EUVD-2021-18730

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

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.

Patch / fix

  • kf5-messagelib Debian 12 4:20.08.3-5

debian advisories DEBIAN-CVE-2021-31855

  • messagelib openSUSE Tumbleweed 21.08.1-1.2

opensuse advisories openSUSE-SU-2024:11046-1

  • messagelib Arch Linux 21.04.0-2

arch linux advisories AVG-1897

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-31855 updated cvss 5.3

kmail: deleting attachments can disclose content of encrypted messages

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:P/I:N/A:N

Classification

Weakness
  • CWE-312 Cleartext Storage of Sensitive Information

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.