# CVE-2021-35121: Use after free in Snapdragon Compute, Snapdragon Connectivity, Snapdragon Industrial IOT, Snapdragon Mobile

> A use-after-free vulnerability in the Synx driver allows attackers to execute arbitrary code or escalate privileges on Qualcomm Snapdragon devices.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Jun 2022
- **Updated:** 4 Aug 2024
- **Also known as:** 3018966, A-209480901, GHSA-jj9r-hxfw-c62h, PUB-A-209480901

## What is CVE-2021-35121?

CVE-2021-35121 is a medium-severity use after free vulnerability in Qualcomm Apq8053 Firmware, published on 14 Jun 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An array index is improperly used to lock and unlock a mutex which can lead to a Use After Free condition In the Synx driver in Snapdragon Compute, Snapdragon Connectivity, Snapdragon Industrial IOT, Snapdragon Mobile

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2021-35121?

It affects 44 products.


Products: Qualcomm Apq8053 Firmware, Qualcomm Msm8953 Firmware, Qualcomm Qca6390 Firmware, Qualcomm Qca6391 Firmware, Qualcomm Qca6426 Firmware, Qualcomm Qca6436 Firmware, Qualcomm Qcm2290 Firmware, Qualcomm Qcm4290 Firmware, Qualcomm Qcs2290 Firmware, Qualcomm Qcs4290 Firmware, Qualcomm Qrb5165 Firmware, Qualcomm Qrb5165m Firmware, Qualcomm Qrb5165n Firmware, Qualcomm Sd460 Firmware, Qualcomm Sd662 Firmware, Qualcomm Sd680 Firmware, Qualcomm Sd690 5g Firmware, Qualcomm Sd750g Firmware, Qualcomm Sd765 Firmware, Qualcomm Sd765g Firmware and 24 more.

## How do I fix CVE-2021-35121?

Apply the vendor's patch.

## Is CVE-2021-35121 being exploited?

There is no known exploitation of CVE-2021-35121 in the wild and no public exploit code.

## Other vulnerabilities in Qualcomm Apq8053 Firmware

- [CVE-2022-22071](https://insights.sbomify.com/CVE-2022-22071/): Qualcomm Multiple Chipsets Use-After-Free (high 8.4, exploited in the wild)
- [CVE-2020-11153](https://insights.sbomify.com/CVE-2020-11153/): Memory corruption in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer Electronics Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile (critical 9.8)
- [CVE-2020-3703](https://insights.sbomify.com/CVE-2020-3703/): Memory corruption in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer Electronics Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon IoT, Snapdragon Mobile, Snapdragon Voice & Music (critical 9.8)
- [CVE-2019-14080](https://insights.sbomify.com/CVE-2019-14080/): Memory corruption in Snapdragon Auto, Snapdragon Compute, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Wearables (critical 9.8)
- [CVE-2020-3628](https://insights.sbomify.com/CVE-2020-3628/): Information disclosure in Snapdragon Consumer IOT, Snapdragon Mobile (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-35121 and fix it if it is affected.

What it is: CVE-2021-35121 is a medium-severity use after free vulnerability in Qualcomm Apq8053 Firmware, published on 14 Jun 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-35121 in the wild and no public exploit code.

Affected product: Qualcomm Apq8053 Firmware. 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-2021-35121/ (Markdown: https://insights.sbomify.com/CVE-2021-35121/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-35121
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-35121
- OSV: https://osv.dev/vulnerability/CVE-2021-35121

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-35121/
Summaries are generated and may contain mistakes; the official description above is the record.