# CVE-2021-27351: Security feature bypass in n/a

> Attackers can maintain access to Telegram accounts because the Terminate Session feature fails to invalidate active sessions.

- **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:** 19 Feb 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-27351, GHSA-cc4r-2rwj-vx7x, UBUNTU-CVE-2021-27351

## What is CVE-2021-27351?

CVE-2021-27351 is a medium-severity vulnerability in n/a, published on 19 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Terminate Session feature in the Telegram application through 7.2.1 for Android, and through 2.4.7 for Windows and UNIX, fails to invalidate a recently active session.

Weakness: CWE-613 (DEPRECATED: Insufficient Session Expiration)

## Which versions are affected by CVE-2021-27351?

It affects 1 product.


Products: Telegram Telegram.

## How do I fix CVE-2021-27351?

Upgrade to a fixed version.

## Is CVE-2021-27351 being exploited?

There is no known exploitation of CVE-2021-27351 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-2021-27351 and fix it if it is affected.

What it is: CVE-2021-27351 is a medium-severity vulnerability in n/a, published on 19 Feb 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-2021-27351 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-2021-27351/ (Markdown: https://insights.sbomify.com/CVE-2021-27351/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27351
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27351
- OSV: https://osv.dev/vulnerability/CVE-2021-27351

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27351/
Summaries are generated and may contain mistakes; the official description above is the record.