# CVE-2021-42716: Memory corruption in n/a

> A buffer overflow in the stb_image library allows attackers to crash services or read heap memory via crafted PNM files.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/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:** 21 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-42716, GHSA-44mr-92xw-jfrv, UBUNTU-CVE-2021-42716, openSUSE-SU-2022:0018-1

## What is CVE-2021-42716?

CVE-2021-42716 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 21 Oct 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

An issue was discovered in stb stb_image.h 2.27. The PNM loader incorrectly interpreted 16-bit PGM files as 8-bit when converting to RGBA, leading to a buffer overflow when later reinterpreting the result as a 16-bit buffer. An attacker could potentially have crashed a service using stb_image, or read up to 1024 bytes of non-consecutive heap data without control over the read location.

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

## Which versions are affected by CVE-2021-42716?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `stb` | SUSE:Package Hub 15 SP3 | All versions | 2.32.1549563867.59e9702-bp153.2.3.1 |
| `stb` | openSUSE:Leap 15.3 | All versions | 2.32.1549563867.59e9702-bp153.2.3.1 |

Products: Fedoraproject Fedora, Nothings Stb Image.h.

## How do I fix CVE-2021-42716?

Upgrade to a fixed version.

## Is CVE-2021-42716 being exploited?

There is no known exploitation of CVE-2021-42716 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42716 and fix it if it is affected.

What it is: CVE-2021-42716 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 21 Oct 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-2021-42716 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2021-42716/ (Markdown: https://insights.sbomify.com/CVE-2021-42716/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42716
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42716
- OSV: https://osv.dev/vulnerability/CVE-2021-42716

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42716/
Summaries are generated and may contain mistakes; the official description above is the record.