CVE-2026-43122

Description

In the Linux kernel, the following vulnerability has been resolved: ACPI: processor: Update cpuidle driver check in __acpi_processor_start() Commit 7a8c994cbb2d ("ACPI: processor: idle: Optimize ACPI idle driver registration") moved the ACPI idle driver registration to acpi_processor_driver_init() and acpi_processor_power_init() does not register an idle driver any more. Accordingly, the cpuidle driver check in __acpi_processor_start() needs to be updated to avoid calling acpi_processor_power_init() without a cpuidle driver, in which case the registration of the cpuidle device in that function would lead to a NULL pointer dereference in __cpuidle_register_device().

CVSS Details

CVSS Score

5.5

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Configurations (Affected Products)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* - VULNERABLE

Linux Kernel versions containing commit 7a8c994cbb2d

Linux Kernel versions prior to fix commit 0089ce1c056aee547115bdc25c223f8f88c08498

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

/*
 * Conceptual PoC for CVE-2026-43122
 * This code attempts to trigger the vulnerable path by interacting with ACPI processor states.
 * Triggering the NULL pointer dereference depends on specific kernel state and hardware.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main() {
    printf("[+] Attempting to trigger ACPI processor idle state logic...\n");
    
    // In a real scenario, this might involve specific sysfs writes or module loads
    // that force the kernel to re-evaluate processor states.
    // The vulnerability occurs internally in __acpi_processor_start.
    
    printf("[*] Vulnerability is triggered during kernel initialization or state change.");
    printf("[!] If vulnerable, the kernel will crash due to NULL pointer dereference.");
    
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43122
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43122
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43122/
[4] VulDB https://vuldb.com/cve/CVE-2026-43122
[5] https://git.kernel.org/stable/c/0089ce1c056aee547115bdc25c223f8f88c08498
[6] https://git.kernel.org/stable/c/68f38f648e4b5bed2aeadd2f711e25302e6490f8
[7] https://git.kernel.org/stable/c/6cfed39c2ce64ac024bbde458a9727105e0b8c66

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43122", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:29.067", "lastModified": "2026-05-12T21:17:44.983", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nACPI: processor: Update cpuidle driver check in __acpi_processor_start()\n\nCommit 7a8c994cbb2d (\"ACPI: processor: idle: Optimize ACPI idle\ndriver registration\") moved the ACPI idle driver registration to\nacpi_processor_driver_init() and acpi_processor_power_init() does\nnot register an idle driver any more.\n\nAccordingly, the cpuidle driver check in __acpi_processor_start() needs\nto be updated to avoid calling acpi_processor_power_init() without a\ncpuidle driver, in which case the registration of the cpuidle device\nin that function would lead to a NULL pointer dereference in\n__cpuidle_register_device()."}], "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-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "6.18.14", "matchCriteriaId": "3E0E101B-8972-4E77-80E0-D97AC3CA57C1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.4", "matchCriteriaId": "672A3E79-EC03-479D-8503-361DFBDC8092"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/0089ce1c056aee547115bdc25c223f8f88c08498", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/68f38f648e4b5bed2aeadd2f711e25302e6490f8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6cfed39c2ce64ac024bbde458a9727105e0b8c66", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}