CVE-2026-33192

MEDIUM

free5GC UDM incorrectly returns 500 for empty supi path parameter in PATCH sdm-subscriptions reques

Title source: cna
STIX 2.1

Description

Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. In versions prior to 1.4.2, the UDM incorrectly converts a downstream 400 Bad Request (from UDR) into a 500 Internal Server Error when handling PATCH requests with an empty supi path parameter. Additionally, the UDM incorrectly translates the PATCH method to PUT when forwarding to UDR, indicating a deeper architectural issue. This leaks internal error handling behavior, making it difficult for clients to distinguish between client-side errors and server-side failures. The issue has been patched in version 1.4.2.

References (3)

Core 3
Core References
X_Refsource_Misc x_refsource_misc
https://github.com/free5gc/free5gc/issues/784
X_Refsource_Misc x_refsource_misc
https://github.com/free5gc/udm/pull/79

Scores

CVSS v3 5.3
EPSS 0.0032
EPSS Percentile 24.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-209
Status published
Products (3)
free5gc/free5gc < 1.4.2
free5gc/udm < 1.4.2
free5gc/udm 0 - 1.4.2Go
Published Mar 20, 2026
Tracked Since Mar 20, 2026