CVE-2026-33065

free5GC UDM incorrectly returns 500 for empty supi path parameter in DELETE sdm-subscriptions request

MEDIUM
5.3
CVSS Score
Published: March 20, 2026 at 08:03 AM UTC
Updated: June 17, 2026 at 10:36 AM UTC
2 products affected across 1 vendorUdmFREE5GC

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.3%
SSVC
PoC

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 DELETE requests with an empty supi path parameter. This leaks internal error handling behavior and makes it difficult for clients to distinguish between client-side errors and server-side failures. When a client sends a DELETE request with an empty supi (e.g., double slashes // in URL path), the UDM forwards the malformed request to UDR, which correctly returns 400. However, UDM propagates this as 500 SYSTEM_FAILURE instead of returning the appropriate 400 error to the client. This violates REST API best practices for DELETE operations. The issue has been patched in version 1.4.2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.4.2
v < 1.4.2
Affected range stops below 1.4.2, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMPatchVendor Advisory
Source: cverecord
https://github.com/free5gc/free5gc/security/advisories/GHSA-958m-gxmc-mccm
x_refsource_MISCExploitIssue TrackingPatchVendor Advisory
Source: cverecord
https://github.com/free5gc/free5gc/issues/783
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/free5gc/udm/pull/79

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-209

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