# CVE-2020-6016: Memory corruption in Game Networking Sockets

> A heap-based buffer underflow in Valve's Game Networking Sockets library allows remote attackers to potentially execute arbitrary code via crafted unreliable segments.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Nov 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-2rgm-7354-cfw6

## What is CVE-2020-6016?

CVE-2020-6016 is a critical memory corruption vulnerability in Game Networking Sockets, published on 18 Nov 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Valve's Game Networking Sockets prior to version v1.2.0 improperly handles unreliable segments with negative offsets in function SNP_ReceiveUnreliableSegment(), leading to a Heap-Based Buffer Underflow and a free() of memory not from the heap, resulting in a memory corruption and probably even a remote code execution.

Weakness: CWE-787 (Out-of-bounds Write), CWE-590 (Free of Memory not on the Heap)

## Which versions are affected by CVE-2020-6016?

It affects 1 product.


Products: Valvesoftware Game Networking Sockets.

## How do I fix CVE-2020-6016?

No fix has been published for CVE-2020-6016 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-6016 being exploited?

There is no known exploitation of CVE-2020-6016 in the wild and no public exploit code.

## Other vulnerabilities in Game Networking Sockets

- [CVE-2020-6017](https://insights.sbomify.com/CVE-2020-6017/): Memory corruption in Game Networking Sockets (critical 9.8)
- [CVE-2020-6018](https://insights.sbomify.com/CVE-2020-6018/): Memory corruption in Game Networking Sockets (critical 9.8)
- [CVE-2020-6019](https://insights.sbomify.com/CVE-2020-6019/): Denial of service in Game Networking Sockets (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-6016 and fix it if it is affected.

What it is: CVE-2020-6016 is a critical memory corruption vulnerability in Game Networking Sockets, published on 18 Nov 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-6016 in the wild and no public exploit code.

Affected product: Game Networking Sockets. 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-2020-6016/ (Markdown: https://insights.sbomify.com/CVE-2020-6016/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-6016
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-6016
- OSV: https://osv.dev/vulnerability/CVE-2020-6016

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-6016/
Summaries are generated and may contain mistakes; the official description above is the record.