Vulnerability · Published Apr 21, 2026 · Assigned by GitHub_M
CVE-2026-41135free5GC PCF: Memory Leak via CORS Middleware Registration in HTTP Handler Leads to Denial of Service
High 7.5
In plain English
A high-severity uncontrolled resource consumption in pcf from free5gc. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/free5gc/pcf | 1.4.3 | GHSA-98cp-84m9-q3qp |
| Go | github.com/free5gc/pcf | 1.4.3 | GO-2026-5278 |
Affected products (as reported)
Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H