# CVE-2023-37021: Denial of service in n/a

> Remote attackers can crash the Open5GS MME by sending malformed S1AP packets, causing a denial of service in 5G core networks.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/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:** 22 Jan 2025
- **Updated:** 6 Feb 2025
- **Also known as:** GHSA-2g4r-3v66-3h7f

## What is CVE-2023-37021?

CVE-2023-37021 is a high-severity denial of service vulnerability in Open5gs Open5gs, published on 22 Jan 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Open5GS MME version <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `UE Context Modification Failure` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2023-37021?

It affects 1 product.


Products: Open5gs Open5gs.

## How do I fix CVE-2023-37021?

No fix has been published for CVE-2023-37021 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-37021 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-37021 exists.

## Other vulnerabilities in Open5gs Open5gs

- [CVE-2024-40130](https://insights.sbomify.com/CVE-2024-40130/): Memory corruption in n/a (critical 9.8)
- [CVE-2021-28122](https://insights.sbomify.com/CVE-2021-28122/): Missing authorization in n/a (critical 9.8)
- [CVE-2021-25863](https://insights.sbomify.com/CVE-2021-25863/): Hardcoded credentials in n/a (high 8.8)
- [CVE-2025-41067](https://insights.sbomify.com/CVE-2025-41067/): Reachable Assertion vulnerability in Open5GS (high 8.7)
- [CVE-2025-41068](https://insights.sbomify.com/CVE-2025-41068/): Reachable Assertion vulnerability in Open5GS (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-37021 and fix it if it is affected.

What it is: CVE-2023-37021 is a high-severity denial of service vulnerability in Open5gs Open5gs, published on 22 Jan 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-37021 exists.

Affected product: Open5gs Open5gs. 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-2023-37021/ (Markdown: https://insights.sbomify.com/CVE-2023-37021/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-37021
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-37021
- OSV: https://osv.dev/vulnerability/CVE-2023-37021

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-37021/
Summaries are generated and may contain mistakes; the official description above is the record.