How severe is CVE-2021-31855?

CVE-2021-31855 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-31855 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31855?

CVE-2021-31855 affects Kde Messagelib. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-31855?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-31855 published?

CVE-2021-31855 was published on 2021-06-02 and last updated on 2026-06-17.

CVE-2021-31855

CVE-2021-31855 is a medium-severity vulnerability in Kde Messagelib with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-312.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-312
Affected product: Kde Messagelib
Published: 2021-06-02
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-31855?: 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.
How severe is CVE-2021-31855?: CVE-2021-31855 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-31855 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31855?: CVE-2021-31855 affects Kde Messagelib. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-31855?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-31855 published?: CVE-2021-31855 was published on 2021-06-02 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:kde:messagelib:*:*:*:*:*:*:*:*

More vulnerabilities in Kde Messagelib

CVE-2017-9604 — High (CVSS 7.5): KDE kmail before 5.5.2 and messagelib before 5.5.2, as distributed in KDE Applications before 17.04.2, do not ensure…

All CVEs affecting Kde Messagelib →

Other CWE-312 (Cleartext Storage of Sensitive Information) vulnerabilities

CVE-2022-43757 — Critical (CVSS 9.9): A Cleartext Storage of Sensitive Information vulnerability in SUSE Rancher allows users on managed clusters to gain…
CVE-2021-36782 — Critical (CVSS 9.9): A Cleartext Storage of Sensitive Information vulnerability in SUSE Rancher allows authenticated Cluster Owners, Cluster…
CVE-2020-9045 — Critical (CVSS 9.9): During installation or upgrade to Software House C•CURE 9000 v2.70 and American Dynamics victor Video Management…
CVE-2026-31848 — Critical (CVSS 9.8): Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 uses the ecos_pw cookie for authentication, which…
CVE-2025-65826 — Critical (CVSS 9.8): The mobile application was found to contain stored credentials for the network it was developed on. If an attacker…
CVE-2025-34206 — Critical (CVSS 9.8): Vasion Print (formerly PrinterLogic) Virtual Appliance Host and Application (VA and SaaS deployments) mount host…

Browse all CWE-312 (Cleartext Storage of Sensitive Information) vulnerabilities →