# CVE-2021-27499: Weak cryptography in Ypsomed mylife Cloud, mylife Mobile Application

> Man-in-the-middle attackers can tamper with messages due to non-random IVs in the application layer encryption of the Ypsomed mylife App and Cloud communication.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-47g5-g8gc-h4qg

## What is CVE-2021-27499?

CVE-2021-27499 is a medium-severity vulnerability in Ypsomed mylife Cloud, mylife Mobile Application, published on 2 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Ypsomed mylife Cloud, mylife Mobile Application, Ypsomed mylife Cloud: All versions prior to 1.7.2, Ypsomed mylife App: All versions prior to 1.7.5,The application layer encryption of the communication protocol between the Ypsomed mylife App and mylife Cloud uses non-random IVs, which allows man-in-the-middle attackers to tamper with messages.

Weakness: CWE-330 (Use of Insufficiently Random Values), CWE-329 (Generation of Predictable IV with CBC Mode)

## Which versions are affected by CVE-2021-27499?

It affects 2 products.


Products: Ypsomed Mylife, Ypsomed Mylife Cloud.

## How do I fix CVE-2021-27499?

No fix has been published for CVE-2021-27499 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27499 being exploited?

There is no known exploitation of CVE-2021-27499 in the wild and no public exploit code.

## Other vulnerabilities in Ypsomed mylife Cloud, mylife Mobile Application

- [CVE-2021-27491](https://insights.sbomify.com/CVE-2021-27491/): Information disclosure in Ypsomed mylife Cloud, mylife Mobile Application (high 7.5)
- [CVE-2021-27495](https://insights.sbomify.com/CVE-2021-27495/): Information disclosure in Ypsomed mylife Cloud, mylife Mobile Application (high 7.1)
- [CVE-2021-27503](https://insights.sbomify.com/CVE-2021-27503/): Hardcoded credentials in Ypsomed mylife Cloud, mylife Mobile Application (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27499 and fix it if it is affected.

What it is: CVE-2021-27499 is a medium-severity vulnerability in Ypsomed mylife Cloud, mylife Mobile Application, published on 2 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-27499 in the wild and no public exploit code.

Affected product: Ypsomed mylife Cloud, mylife Mobile Application. 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-2021-27499/ (Markdown: https://insights.sbomify.com/CVE-2021-27499/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27499
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27499
- OSV: https://osv.dev/vulnerability/CVE-2021-27499

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27499/
Summaries are generated and may contain mistakes; the official description above is the record.