CVE-2023-37023
Published: 22 January 2025
Summary
CVE-2023-37023 is a high-severity Reachable Assertion (CWE-617) vulnerability in Open5Gs Open5Gs. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 45.9% 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 SI-10 (Information Input Validation) and SI-11 (Error Handling).
Deeper analysis
CVE-2023-37023 is a reachable assertion vulnerability (CWE-617) affecting Open5GS Mobility Management Entity (MME) versions up to and including 2.6.4. The issue resides in the Uplink NAS Transport packet handler, where a packet missing its MME_UE_S1AP_ID field triggers an assertion failure, causing the Open5GS MME to crash. This flaw was published on 2025-01-22 and carries a CVSS v3.1 base score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H), indicating high severity due to its potential for significant availability disruption.
Any unauthenticated attacker with network access to the affected Open5GS MME can exploit this vulnerability by sending specially crafted Uplink NAS Transport packets lacking the required MME_UE_S1AP_ID field. A single such packet crashes the service, and repeated transmissions enable a denial-of-service condition, rendering the MME unavailable. The attack requires low complexity, no user interaction, and exploits a scope change to amplify impact across the system.
Mitigation details and patches are outlined in the advisory available at https://cellularsecurity.org/ransacked. Security practitioners should consult this reference for upgrade guidance to versions beyond 2.6.4 and any interim workarounds.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-40943
Vulnerability details
Open5GS MME versions <= 2.6.4 contain a reachable assertion in the `Uplink NAS Transport` packet handler. A packet missing its `MME_UE_S1AP_ID` field causes Open5gs to crash; an attacker may repeatedly send such packets to cause denial of service.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct exploitation of public-facing MME service via crafted packets leads to application crash (service exhaustion via vulnerability exploitation).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Validates incoming Uplink NAS Transport packets to reject malformed ones missing the MME_UE_S1AP_ID field, directly preventing the assertion failure and crash.
Ensures the packet handler gracefully manages errors from missing MME_UE_S1AP_ID without triggering an assertion crash.
Remediates the specific assertion vulnerability by applying patches to Open5GS MME versions beyond 2.6.4 as advised.