In recent years, the security of embedded and mobile platforms has gained more focus as society increasingly relies on devices powered by complex chips. One such chip ecosystem is Qualcomm's Snapdragon, which is used in a wide range of devices — from smartphones to cars and wearable devices.

In this article, we'll talk about a critical vulnerability, CVE-2022-22085, that affects multiple Snapdragon platforms. You’ll learn what the bug is, how attackers might exploit it, some code snippets to illustrate the problem, and pointers to original references for more detail.

What is CVE-2022-22085?

CVE-2022-22085 is a vulnerability caused by a buffer overflow in the video module used by Qualcomm's Snapdragon chips. The issue resides in the way the video driver reads specially crafted .dts (Device Tree Source or possibly a renamed file used for video information) files. Improper bounds checking when reading and copying data from the file can lead to memory corruption.

Severity: High  
Attack vector: Local/Physical (opening a file or triggering a video decode)  
Impact: Denial of Service, possible code execution

Official Description

> "Memory corruption in video due to buffer overflow while reading the dts file in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music, Snapdragon Wearables."

(Source: Qualcomm Security Bulletin)

Wearables: Watches, fitness trackers.

> If your device uses Qualcomm Snapdragon chipsets and has not been patched since mid-2022, it may be vulnerable.

How Does the Vulnerability Work?

The vulnerable code reads data from a .dts file (associated with video processing or decompression), loading its contents into a fixed-size buffer. The code *assumes* that the input data will never be larger than the buffer. But, a maliciously crafted file can have more data than the buffer can handle, causing an overflow.

Data spills outside the intended memory location.

- This can corrupt adjacent memory structures, crash the process, or, in the worst case, allow the attacker to run their own code on the device.

Let’s look at a simplified pseudo-C example mirroring the vulnerable logic

#include <stdio.h>
#include <string.h>

// Hypothetical vulnerable function
void read_dts_file(FILE *file) {
    char buffer[1024];
    size_t read_bytes;

    // Vulnerable: does NOT check how much data is in the file
    read_bytes = fread(buffer, 1, 4096, file);  
    // Should be fread(buffer, 1, sizeof(buffer), file);

    // Further processing...
}

*What’s wrong here?*  
The buffer is just 1024 bytes, but the code reads up to 4096 bytes from the file, causing a buffer overflow if the input file is larger than 1024 bytes.

A safer approach

read_bytes = fread(buffer, 1, sizeof(buffer), file);

How could an attacker exploit this bug?

An attacker would craft a .dts file specifically designed to break the memory structure of the video module. This file could be:

- Sent via an app that processes video/graphics (media player, video call app, etc.).

Crash the video service (leading to a Denial of Service).

- Potentially overwrite function return pointers, allowing the attacker to run their own code and even gain higher privileges.

Results: Video module crashes, or attacker’s code is executed under the module’s privileges.

> Note: No public exploit is widely available yet, but due to the simplicity of the bug (a classic buffer overflow), crafting a working exploit is within the realm of skilled attackers, especially with knowledge of the specific chip and software version.

Proof-of-Concept (PoC)

While responsible disclosure prevents us from posting a live exploit, here’s a harmless demonstration of the crash:

# overflow_dts.py: Creates a file that will overflow the buffer
with open("overflow.dts", "wb") as f:
    f.write(b"A" * 4096)  # 4096 bytes, which is larger than most buffer sizes

When loaded by a vulnerable system, this file could trigger a crash, revealing susceptibility to the bug.

Check with your device manufacturer ("OEM") for firmware updates.

- Make sure your device is up-to-date with the latest security patches, especially if you haven’t updated since mid-2022.

What else can you do?

- Avoid Unknown Files: Don’t open .dts (or other video/configuration) files from untrusted sources.

Update Regularly: Enable auto-updates on IoT and connected devices.

- Monitor Security News: For your device, check for updates from vendors if you hear about active exploitation.

References and Resources

- Qualcomm Security Bulletin July 2022
- National Vulnerability Database Entry: CVE-2022-22085
- Mitre CVE Entry
- Qualcomm Security Center

Conclusion

CVE-2022-22085 is a serious vulnerability affecting a vast range of devices using Snapdragon chips. The flaw—an unchecked buffer size—remains a textbook example of how simple programming mistakes can have widespread, serious consequences. Device users and manufacturers should prioritize patching and follow safe security practices to defend against such memory corruption bugs.

If you are a developer or maintain code for embedded or IoT platforms, always remember: check your buffer sizes! A single oversight can compromise millions.

Timeline

Published on: 06/14/2022 10:15:00 UTC
Last modified on: 06/22/2022 16:23:00 UTC