CVE-2026-33063: free5GC AUSF UE Authentication Panic on Nil SuciSupiMap Interface Conversion

Impact This is an Improper Null Check vulnerability leading to Denial of Service.

• Security Impact: A remote attacker can cause the AUSF service to panic and crash by sending a crafted UE authentication request that triggers a nil interface conversion in the GetSupiFromSuciSupiMap function. This results in complete denial of service for the AUSF authentication service.
• Functional Impact: The GetSupiFromSuciSupiMap function attempts to perform an interface conversion from interface{} to *context.SuciSupiMap without checking if the underlying value is nil. When SuciSupiMap is nil, the code panics with “interface conversion: interface {} is nil, not *context.SuciSupiMap”.
• Affected Parties: All deployments of free5GC v4.0.1 using the AUSF UE authentication service (/nausf-auth/v1/ue-authentications endpoint).

Patches Yes, the issue has been patched. The fix is implemented in PR free5gc/ausf#52 (commit: [add specific commit hash if available]). Users should upgrade to the next release of free5GC that includes this commit.

Workarounds There is no direct workaround at the application level. The recommendation is to apply the provided patch or restrict access to the AUSF API to trusted sources only.