# CVE-2021-31855: Information disclosure in n/a

> KDE Messagelib leaks cleartext of encrypted messages to remote servers when attachments are deleted, allowing attackers with server access to read sensitive data.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-31855, GHSA-h76g-vp43-8cw5, MGASA-2021-0208, UBUNTU-CVE-2021-31855

## What is CVE-2021-31855?

CVE-2021-31855 is a medium-severity vulnerability in n/a, published on 2 Jun 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-312 (Cleartext Storage of Sensitive Information)

## Which versions are affected by CVE-2021-31855?

It affects 1 product.


Products: Kde Messagelib.

## How do I fix CVE-2021-31855?

Apply the vendor's patch.

## Is CVE-2021-31855 being exploited?

There is no known exploitation of CVE-2021-31855 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31855 and fix it if it is affected.

What it is: CVE-2021-31855 is a medium-severity vulnerability in n/a, published on 2 Jun 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-31855 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-31855/ (Markdown: https://insights.sbomify.com/CVE-2021-31855/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31855
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31855
- OSV: https://osv.dev/vulnerability/CVE-2021-31855

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31855/
Summaries are generated and may contain mistakes; the official description above is the record.