CVE-2026-41135
free5GC PCF: Memory Leak via CORS Middleware Registration in HTTP Handler Leads to Denial of Service
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.
INFO
Published Date :
April 22, 2026, 12:16 a.m.
Last Modified :
April 23, 2026, 7:41 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update free5GC UDR to version 1.4.3.
- Apply the patch for the CORS middleware handler chain.
- Monitor memory usage after the update.
Public PoC/Exploit Available at Github
CVE-2026-41135 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-41135.
| URL | Resource |
|---|---|
| https://github.com/free5gc/free5gc/security/advisories/GHSA-98cp-84m9-q3qp | Exploit Vendor Advisory |
| https://github.com/free5gc/pcf/commit/599803b1b2eb4611e26d5216481ee142bce71a16 | Patch |
| https://github.com/free5gc/free5gc/security/advisories/GHSA-98cp-84m9-q3qp | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-41135 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-41135
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Shell
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-41135 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-41135 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 23, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:* versions up to (including) 4.2.1 *cpe:2.3:a:free5gc:pcf:*:*:*:*:*:*:*:* versions up to (excluding) 1.4.3 Added Reference Type GitHub, Inc.: https://github.com/free5gc/free5gc/security/advisories/GHSA-98cp-84m9-q3qp Types: Exploit, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/free5gc/pcf/commit/599803b1b2eb4611e26d5216481ee142bce71a16 Types: Patch Added Reference Type CISA-ADP: https://github.com/free5gc/free5gc/security/advisories/GHSA-98cp-84m9-q3qp Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Apr. 22, 2026
Action Type Old Value New Value Added Reference https://github.com/free5gc/free5gc/security/advisories/GHSA-98cp-84m9-q3qp -
New CVE Received by [email protected]
Apr. 22, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-400 Added Reference https://github.com/free5gc/free5gc/security/advisories/GHSA-98cp-84m9-q3qp Added Reference https://github.com/free5gc/pcf/commit/599803b1b2eb4611e26d5216481ee142bce71a16