CVE-2025-70123
Published: 13 February 2026
Summary
CVE-2025-70123 is a high-severity Improper Input Validation (CWE-20) vulnerability in Free5Gc Free5Gc. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked in the top 47.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2025-70123 is an improper input validation and protocol compliance vulnerability (CWE-20) in free5GC version 4.0.1, specifically affecting the User Plane Function (UPF) component. Published on 2026-02-13, it carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). The issue stems from the UPF incorrectly accepting a malformed PFCP Association Setup Request, which violates 3GPP TS 29.244 standards. This misacceptance leaves the UPF in an inconsistent state, enabling subsequent valid PFCP Session Establishment Requests to provoke a cascading failure.
Remote, unauthenticated attackers can exploit this vulnerability over the network with low complexity and no user interaction required. By first sending a malformed PFCP Association Setup Request and then a legitimate PFCP Session Establishment Request, an attacker disrupts the UPF's connection to the Session Management Function (SMF), causing denial of service through service degradation across the affected 5G core network.
Mitigation details are discussed in the upstream GitHub issue at https://github.com/free5gc/free5gc/issues/745.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-207535
Vulnerability details
An improper input validation and protocol compliance vulnerability in free5GC v4.0.1 allows remote attackers to cause a denial of service. The UPF incorrectly accepts a malformed PFCP Association Setup Request, violating 3GPP TS 29.244. This places the UPF in an…
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inconsistent state where a subsequent valid PFCP Session Establishment Request triggers a cascading failure, disrupting the SMF connection and causing service degradation.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Malformed PFCP request exploitation directly triggers UPF service crash and DoS via application-level vulnerability (T1499.004).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly addresses the improper input validation vulnerability by requiring the UPF to validate PFCP Association Setup Requests against 3GPP TS 29.244 standards, rejecting malformed inputs before they cause an inconsistent state.
Protects against the denial-of-service impact by limiting the effects of malformed PFCP requests and the resulting cascading failure disrupting SMF connectivity.
Ensures the UPF fails to a known secure state after processing a malformed PFCP Association Setup Request, mitigating the inconsistent state that enables subsequent valid requests to trigger cascading failure.