Medium severity · published Mar 20, 2026
CVE-2026-33192
free5GC UDM incorrectly returns 500 for empty supi path parameter in PATCH sdm-subscriptions reques
5.3
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 26% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
free5gc · free5gc
< 1.4.2 · source: vendor
UD
Udm · Free5gc
before 1.4.2 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33192
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33192
Exploit
https://github.com/free5gc/free5gc/issues/784
Patch
https://github.com/free5gc/free5gc/security/advisories/GHSA-5rvc-5cwx-g5x8
Issue Tracking
https://github.com/free5gc/udm/pull/79
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