CVE-2026-41135 free5GC PCF: Memory Leak via CORS Middleware Registration in HTTP Handler Leads to Denial of Service
Unauthenticated attackers can cause memory exhaustion and denial of service in free5GC PCF by sending repeated HTTP requests to the OAM endpoint.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-41135?
CVE-2026-41135 is a high-severity denial of service vulnerability in Free5gc Free5gc, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-400
Which versions are affected by CVE-2026-41135?
3 open source packages ship an affected version, including github.com/free5gc/pcf. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
github.com/free5gc/pcf Go | All versions | 1.4.3 |
github.com/free5gc/pcf Go | All versions | 1.4.3 |
github.com/free5gc/pcf Go | All versions | 1.4.3 |
Products include Free5gc Free5gc, Free5gc Pcf.
How do I fix CVE-2026-41135?
Upgrade github.com/free5gc/pcf to 1.4.3 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-41135 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41135 exists.
Other vulnerabilities in Free5gc Free5gc
- CVE-2026-44327 free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler
- CVE-2026-44329 free5GC's SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers
- CVE-2026-44330 free5GC's NEF nnef-pfdmanagement API is unauthenticated; forged bearer tokens can read PFD data and create/delete PFD subscriptions
- CVE-2025-63679 Memory corruption in n/a
- CVE-2026-44315 free5GC's NEF 3gpp-pfd-management API is unauthenticated; forged bearer tokens can create, read, and delete PFD transactions
Sources
Also known as GHSA-98cp-84m9-q3qp, GO-2026-5278.