A reachable assertion in the mme_ue_find_by_imsi function of Open5GS <= 2.6.4 allows attackers to cause a Denial of Service (DoS) via a crafted NAS packet.

Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `Initial UE Message` missing a required `NAS_PDU` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a sufficiently large ASN.1 packet over the S1AP interface. An attacker may repeatedly send such an oversized packet to cause the `ogs_sctp_recvmsg` routine to reach an unexpected network state and crash, leading to denial of service.

Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `Path Switch Request` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `UE Context Modification Response` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `S1Setup Request` message missing a required `Global eNB ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `UE Capability Info Indication` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `S1Setup Request` message missing a required `Supported TAs` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `UE Context Release Complete` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME version <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `UE Context Modification Failure` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `E-RAB Modification Indication` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `E-RAB Setup Response` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `Initial Context Setup Response` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `Initial Context Setup Failure` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `Handover Request Ack` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `Handover Cancel` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain a buffer overflow in the ASN.1 deserialization function of the S1AP handler. This buffer overflow causes type confusion in decoded fields, leading to invalid parsing and freeing of memory. An attacker may use this to crash an MME or potentially execute code in certain circumstances.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `Handover Notification` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send an `eNB Status Transfer` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.

Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the S1AP interface. An attacker may send a `Handover Required` message missing a required `MME_UE_S1AP_ID` field to repeatedly crash the MME, resulting in denial of service.