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

Source: https://junglewise.ai/threats/cve-2026-41135-free5gc-pcf-memory-leak-via-cors-middleware-registration-in-http  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-22. Updated: 2026-05-11  
License: CC BY 4.0 with a link back

CVE-2026-41135 · Severity: high · CVSS 7.5 · Published 2026-04-22

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.

Technologies: [free5GC](https://junglewise.ai/threats/technologies/free5gc), [free5GC PCF](https://junglewise.ai/threats/technologies/pcf), [github.com/free5gc/pcf (Go)](https://junglewise.ai/threats/technologies/github-com-free5gc-pcf). Vendors: [free5GC](https://junglewise.ai/threats/vendors/free5gc), [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-41135 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-41135 being exploited in the wild.

**How severe is CVE-2026-41135?** High severity, with a CVSS score of 7.5, published 22 April 2026.

**Which products and versions are affected?** github.com/free5gc/pcf (Go) < 1.4.3, SEMVER:introduced=0,fixed=1.4.3.

**Is there a fix for CVE-2026-41135?** Yes. github.com/free5gc/pcf (Go): upgrade to 1.4.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-41135?** Check whether you run free5GC, free5GC PCF or github.com/free5gc/pcf (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/free5gc/pcf (Go): upgrade to 1.4.3 or later

  ```sh
  go get github.com/free5gc/pcf@v1.4.3
  ```


## Affected products

- free5GC
- free5GC PCF
- github.com/free5gc/pcf (Go) < 1.4.3, SEMVER:introduced=0,fixed=1.4.3

## Identifiers

- CVE-2026-41135
- GHSA-98cp-84m9-q3qp
- GO-2026-5278

## References

- [https://api.github.com/users/Giancannella](https://api.github.com/users/Giancannella)
- [https://github.com/Giancannella](https://github.com/Giancannella)
- [https://api.github.com/users/Giancannella/gists%7B/gist_id%7D](https://api.github.com/users/Giancannella/gists%7B/gist_id%7D)
- [https://api.github.com/users/Giancannella/repos](https://api.github.com/users/Giancannella/repos)
- [https://avatars.githubusercontent.com/u/56028149?v=4](https://avatars.githubusercontent.com/u/56028149?v=4)
- [https://api.github.com/users/Giancannella/events%7B/privacy%7D](https://api.github.com/users/Giancannella/events%7B/privacy%7D)

## Related threats

- [Free5GC SMF resource exhaustion in PFCP session establishment](https://junglewise.ai/threats/cve-2026-106805-a-resource-exhaustion-issue-exists-in-free5gc-v4-2-3-during-pfcp)
- [Free5GC race condition in GMM handler RanUe context access](https://junglewise.ai/threats/cve-2026-94043-a-vulnerability-was-determined-in-free5gc-up-to-4-2-3-this)
- [Free5GC UPF nil pointer dereference in PFCP Session Report](https://junglewise.ai/threats/cve-2026-75439-free5gc-upf-nil-pointer-dereference-in-pfcp-session-report)
- [free5GC NRF input validation bypass in NF profile registration](https://junglewise.ai/threats/cve-2026-55068-free5gc-nrf-input-validation-bypass-in-nf-profile-registration)
- [free5gc NSSF nil pointer dereference in NssaiAvailabilitySubscriptionCreate](https://junglewise.ai/threats/cve-2026-30073-free5gc-nssf-nil-pointer-dereference-in)