A vulnerability in Open5GS versions up to 2.7.7 allows remote manipulation of the ueContext.mmContextList[*].allowedNssai field in the AMF component’s amf_namf_comm_decode_ue_mm_context_list function, causing memory corruption as defined by CWE‑119. The flaw is triggered by crafted input received over the network and can lead to unpredictable program behavior, which may compromise system stability or confidentiality if exploited further. The issue is publicly disclosed and may be utilized by attackers.

The Open5GS open-source project, specifically the AMF module in the Open5GS software, is affected. Versions up to and including 2.7.7 are vulnerable; the 2.8.0 release provides a fix.

The CVSS score of 5.3 indicates moderate severity, and the EPSS score is not available. The vulnerability is not listed in CISA’s KEV catalog, but the attack vector is remote and the exploit has been publicly disclosed, meaning there is a tangible risk of exploitation. Given the lack of an official workaround, the primary mitigation is to upgrade the affected component.