# CVE-2021-22547: Buffer overrun in Google Cloud IoT Device SDK for Embedded C

> A buffer overrun in the Google Cloud IoT Device SDK allows attackers to access heap memory, potentially leading to code execution or data disclosure.

- **Severity:** Medium 6.3 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-q368-635x-gcfv

## What is CVE-2021-22547?

CVE-2021-22547 is a medium-severity memory corruption vulnerability in Google Cloud IoT Device SDK for Embedded C, published on 4 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In IoT Devices SDK, there is an implementation of calloc() that doesn't have a length check. An attacker could pass in memory objects larger than the buffer and wrap around to have a smaller buffer than required, allowing the attacker access to the other parts of the heap. We recommend upgrading the Google Cloud IoT Device SDK for Embedded C used to 1.0.3 or greater.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2021-22547?

It affects 1 product.


Products: Google Cloud Iot Device Sdk for Embedded C.

## How do I fix CVE-2021-22547?

No fix has been published for CVE-2021-22547 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-22547 being exploited?

There is no known exploitation of CVE-2021-22547 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-22547 and fix it if it is affected.

What it is: CVE-2021-22547 is a medium-severity memory corruption vulnerability in Google Cloud IoT Device SDK for Embedded C, published on 4 May 2021. 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-2021-22547 in the wild and no public exploit code.

Affected product: Google Cloud IoT Device SDK for Embedded C. 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-2021-22547/ (Markdown: https://insights.sbomify.com/CVE-2021-22547/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-22547
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-22547
- OSV: https://osv.dev/vulnerability/CVE-2021-22547

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-22547/
Summaries are generated and may contain mistakes; the official description above is the record.