# CVE-2026-90707: Open5GS Old AMF Discovery Fallback nnrf-handler.c amf_nnrf_try_old_amf_discovery_fallback use after free

> Remote attackers can trigger a use-after-free in Open5GS AMF discovery, potentially leading to code execution or service disruption.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-wxvq-3xfq-q746

## What is CVE-2026-90707?

CVE-2026-90707 is a medium-severity use after free vulnerability in Open5GS, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A security flaw has been discovered in Open5GS up to 2.7.x. Affected is the function amf_nnrf_try_old_amf_discovery_fallback of the file src/amf/nnrf-handler.c of the component Old AMF Discovery Fallback. The manipulation of the argument discovery_option results in use after free. The attack may be performed from remote. The patch is identified as ddd683a35f8aaac2b7b9884a24cd53bddfc65238. Applying a patch is advised to resolve this issue.

Weakness: CWE-416 (Use After Free), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-90707?


## How do I fix CVE-2026-90707?

No fix has been published for CVE-2026-90707 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-90707 being exploited?

There is no known exploitation of CVE-2026-90707 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90707 and fix it if it is affected.

What it is: CVE-2026-90707 is a medium-severity use after free vulnerability in Open5GS, published on 14 Sep 2026. 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-2026-90707 in the wild and no public exploit code.

Affected product: 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-2026-90707/ (Markdown: https://insights.sbomify.com/CVE-2026-90707/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90707
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90707
- OSV: https://osv.dev/vulnerability/CVE-2026-90707

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90707/
Summaries are generated and may contain mistakes; the official description above is the record.