# CVE-2021-36769: Race condition in n/a

> An attacker can manipulate message ordering on the server, potentially altering the logical sequence of communications in Telegram clients.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Jul 2021
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-36769, GHSA-phpw-4p8w-67hr, UBUNTU-CVE-2021-36769

## What is CVE-2021-36769?

CVE-2021-36769 is a medium-severity vulnerability in n/a, published on 16 Jul 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A reordering issue exists in Telegram before 7.8.1 for Android, Telegram before 7.8.3 for iOS, and Telegram Desktop before 2.8.8. An attacker can cause the server to receive messages in a different order than they were sent a client.

## Which versions are affected by CVE-2021-36769?

It affects 2 products.


Products: Telegram Telegram, Telegram Telegram Desktop.

## How do I fix CVE-2021-36769?

Upgrade to a fixed version.

## Is CVE-2021-36769 being exploited?

There is no known exploitation of CVE-2021-36769 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2019-10044](https://insights.sbomify.com/CVE-2019-10044/): Other in n/a (high 8.8)
- [CVE-2018-20436](https://insights.sbomify.com/CVE-2018-20436/): Server-side request forgery in n/a (high 8.1)
- [CVE-2024-7014](https://insights.sbomify.com/CVE-2024-7014/): Improper multimedia file attachment validation in Telegram for Android app (high 7.1)
- [CVE-2021-31320](https://insights.sbomify.com/CVE-2021-31320/): Memory corruption in n/a (high 7.1)
- [CVE-2021-31321](https://insights.sbomify.com/CVE-2021-31321/): Memory corruption in n/a (high 7.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-36769 and fix it if it is affected.

What it is: CVE-2021-36769 is a medium-severity vulnerability in n/a, published on 16 Jul 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-2021-36769 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-2021-36769/ (Markdown: https://insights.sbomify.com/CVE-2021-36769/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-36769
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-36769
- OSV: https://osv.dev/vulnerability/CVE-2021-36769

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-36769/
Summaries are generated and may contain mistakes; the official description above is the record.