CVE-2026-31776

#include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> // Concept PoC for CVE-2026-31776 // This PoC attempts to trigger the missing index handling in ALSA ctxfi // by interacting with the DSP device. // Note: Actual trigger requires specific hardware (hw20k2). #define DEVICE "/dev/snd/hwC0D0" // Example device path int main() { int fd; printf("[*] Attempting to open ALSA device...\n"); // Open the sound device fd = open(DEVICE, O_RDWR); if (fd < 0) { perror("[-] Failed to open device"); return 1; } printf("[+] Device opened successfully.\n"); // In a real scenario, specific IOCTLs or mixer controls // related to SPDIF1 on hw20k2 would be manipulated here // to hit the daio_device_index() flaw. // The bug causes -EINVAL to be used as an array index. printf("[*] Triggering vulnerability logic flow...\n"); // Placeholder for the specific trigger logic // ioctl(fd, SPECIFIC_TRIGGER_CMD, ...); close(fd); printf("[*] Done.\n"); return 0; }

{"cve": {"id": "CVE-2026-31776", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:40.967", "lastModified": "2026-05-07T02:27:43.700", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: ctxfi: Fix missing SPDIFI1 index handling\n\nSPDIF1 DAIO type isn't properly handled in daio_device_index() for\nhw20k2, and it returned -EINVAL, which ended up with the out-of-bounds\narray access. Follow the hw20k1 pattern and return the proper index\nfor this type, too."}], "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:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-129"}]}], "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/950decf59d4e978b60a792ce0b3e1555a608f489", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b045ab3dff97edae6d538eeff900a34c098761f8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}