Free5GC AMF is vulnerable to DoS through its HandleRegistrationComplete function

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-4531: 0.43% estimated exploitation activity in the next 30 days; percentile 37.81 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

A weakness has been identified in Free5GC 4.1.0. Affected is the function HandleRegistrationComplete of the file internal/gmm/handler.go of the component AMF. Executing a manipulation can lead to denial of service. The attack may be performed from remote. This patch is called 52e9386401ce56ea773c5aa587d4cdf7d53da799. It is best practice to apply a patch to resolve this issue.

Published by the source

22 Mar 2026, 03:30 UTC

Last modified by the source

6 Apr 2026, 05:11 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-xq44-64rg-8g3h

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# Patch Next advisory brief: CVE-2026-4531

Advisory: Free5GC AMF is vulnerable to DoS through its HandleRegistrationComplete function
IDs: CVE-2026-4531, GHSA-xq44-64rg-8g3h
Record: https://patchnext.com/advisories/cve-2026-4531 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/free5gc/amf 1.4.3-0.20260306074636-52e9386401ce. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/free5gc/amf: affected < 1.4.3-0.20260306074636-52e9386401ce; fixed in 1.4.3-0.20260306074636-52e9386401ce

## Suggested inspection (read-only)
- Go github.com/free5gc/amf: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/free5gc/amf.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-xq44-64rg-8g3h (GitHub-reviewed advisory GHSA-xq44-64rg-8g3h lists affected ranges: Go github.com/free5gc/amf >=0 <1.4.3-0.20260306074636-52e9386401ce)

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