free5GC UDM DataChangeNotification Procedure Panic Due to Nil Pointer Dereference

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-33064: 0.50% estimated exploitation activity in the next 30 days; percentile 42.50 (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.

Impact This is a NULL Pointer Dereference vulnerability leading to Denial of Service. - Security Impact: A remote attacker can cause the UDM service to panic and crash by sending a crafted POST request to the /sdm-subscriptions endpoint with a malformed URL path containing path traversal sequences (../) and a large JSON payload. The DataChangeNotificationProcedure function in notifier.go attempts to access a nil pointer without proper validation, causing a complete service crash with "runtime error: invalid memory address or nil pointer dereference". - Functional Impact: The service crashes completely, requiring manual restart. All UDM functionality is disrupted until recovery. - Affected Parties: All deployments of free5GC v4.0.1 using the UDM HTTP callback functionality. Patches Yes, the issue has been patched. The fix is implemented in PR free5gc/udm#78. Users should upgrade to the next release of free5GC that includes this commit. Workarounds There is no direct workaround at the…

Published by the source

18 Mar 2026, 20:06 UTC

Last modified by the source

20 Mar 2026, 21:24 UTC

Source last checked

26 Oct 2026, 15:18 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7g27-v5wj-jr75

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# Patch Next advisory brief: CVE-2026-33064

Advisory: free5GC UDM DataChangeNotification Procedure Panic Due to Nil Pointer Dereference
IDs: CVE-2026-33064, GHSA-7g27-v5wj-jr75
Record: https://patchnext.com/advisories/cve-2026-33064 (revision 1, source checked 26 Oct 2026, 15:18 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
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/udm 1.4.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/free5gc/udm: affected < 1.4.2; fixed in 1.4.2

## Suggested inspection (read-only)
- Go github.com/free5gc/udm: 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/udm.
- 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-7g27-v5wj-jr75 (GitHub-reviewed advisory GHSA-7g27-v5wj-jr75 lists affected ranges: Go github.com/free5gc/udm >=0 <1.4.2)

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