CVE-2026-41135: free5GC PCF: Memory Leak via CORS Middleware Registration in HTTP Handler Leads to Denial of Service

Vulnerability summary

CVE-2026-41135 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in free5gc. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.5% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 21-04-2026
   PublishedVulnerability first disclosed.
2. 22-04-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-400Uncontrolled Resource ConsumptionThe product does not properly control the allocation and maintenance of a limited resource.