# OSV-2026-970: Use-of-uninitialized-value in ogs_cpystrn

> An attacker can cause a denial of service in the 5G NAS library by triggering a use-of-uninitialized-value error during PDU session establishment decoding.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not stated
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Jun 2026

## What is OSV-2026-970?

OSV-2026-970 is a vulnerability in open5gs, published on 27 Jun 2026. It can be exploited over the network, with no action from the victim.

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=527978938

```
Crash type: Use-of-uninitialized-value
Crash state:
ogs_cpystrn
ogs_nas_5gs_decode_dnn
ogs_nas_5gs_decode_pdu_session_establishment_accept
```

## Which versions are affected by OSV-2026-970?

1 open source package ship an affected version, including open5gs.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `open5gs` | OSS-Fuzz | All versions | None |

## How do I fix OSV-2026-970?

No fix has been published for OSV-2026-970 yet. Limit exposure of the affected software until one is available.

## Is OSV-2026-970 being exploited?

There is no known exploitation of OSV-2026-970 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2026-970 and fix it if it is affected.

What it is: OSV-2026-970 is a vulnerability in open5gs, published on 27 Jun 2026. It can be exploited over the network, with no action from the victim.
Exploitation: There is no known exploitation of OSV-2026-970 in the wild and no public exploit code.

Affected packages and fixed versions:
- open5gs (OSS-Fuzz): affected all versions; no fix listed

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/OSV-2026-970/ (Markdown: https://insights.sbomify.com/OSV-2026-970/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2026-970

---
From sbomify Insights: https://insights.sbomify.com/OSV-2026-970/
Summaries are generated and may contain mistakes; the official description above is the record.