CVE-2026-41135

free5GC PCF: Memory Leak via CORS Middleware Registration in HTTP Handler Leads to Denial of Service

HIGH 7.5EPSS 0.5%

free5GC UDR is the Policy Control Function (PCF) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. A memory leak vulnerability in versions prior to 1.4.3 allows any unauthenticated attacker with network access to the PCF SBI interface to cause uncontrolled memory growth by sending repeated HTTP requests to the OAM endpoint. The root cause is a `router.Use()` call inside an HTTP handler that registers a new CORS middleware on every incoming request, permanently growing the Gin router's handler chain. This leads to progressive memory exhaustion and eventual Denial of Service of the PCF, preventing all UEs from obtaining AM and SM policies and blocking 5G session establishment. Version 1.4.3 contains a patch.

Affected: free5gc · pcf
CVSS v3.1 GITHUB: 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.54% chance of exploitation in the next 30 days, 44th percentile
Published: 2026-04-21
Updated: 2026-04-22

Proof-of-concept exploits (1)

advisories/GHSA-98cp-84m9-q3qp

CVE-2026-41135

Proof-of-concept exploits (1)

Security advisories

References