# CVE-2021-31321: Memory corruption in n/a

> A stack-based buffer overflow in the rlottie library allows remote attackers to execute arbitrary code via malicious animated stickers in Telegram clients.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 18 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-31321, GHSA-hqqh-jq4c-g3w3, UBUNTU-CVE-2021-31321

## What is CVE-2021-31321?

CVE-2021-31321 is a high-severity memory corruption vulnerability in n/a, published on 18 May 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Telegram Android <7.1.0 (2090), Telegram iOS <7.1, and Telegram macOS <7.1 are affected by a Stack Based Overflow in the gray_split_cubic function of their custom fork of the rlottie library. A remote attacker might be able to overwrite Telegram's stack memory out-of-bounds on a victim device via a malicious animated sticker.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-31321?

It affects 1 product.


Products: Telegram Telegram.

## How do I fix CVE-2021-31321?

Upgrade to a fixed version.

## Is CVE-2021-31321 being exploited?

There is no known exploitation of CVE-2021-31321 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-2018-15543](https://insights.sbomify.com/CVE-2018-15543/): Auth bypass in n/a (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31321 and fix it if it is affected.

What it is: CVE-2021-31321 is a high-severity memory corruption vulnerability in n/a, published on 18 May 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-31321 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-2021-31321/ (Markdown: https://insights.sbomify.com/CVE-2021-31321/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31321
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31321
- OSV: https://osv.dev/vulnerability/CVE-2021-31321

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31321/
Summaries are generated and may contain mistakes; the official description above is the record.