CVE-2026-23443

Description

In the Linux kernel, the following vulnerability has been resolved: ACPI: processor: Fix previous acpi_processor_errata_piix4() fix After commi f132e089fe89 ("ACPI: processor: Fix NULL-pointer dereference in acpi_processor_errata_piix4()"), device pointers may be dereferenced after dropping references to the device objects pointed to by them, which may cause a use-after-free to occur. Moreover, debug messages about enabling the errata may be printed if the errata flags corresponding to them are unset. Address all of these issues by moving message printing to the points in the code where the errata flags are set.

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 < Commit 2e369ba9eb7b8a06e9cc35a3e7fe73e59272f8c2

Linux Kernel < Commit 68408e8f9e366ad9850a66ac65cb569f13bf6cd4

Linux Kernel < Commit 8583f62259e1b315d5239371adfb36939cdab741

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * Conceptual PoC for CVE-2026-23443
 * This demonstrates the vulnerable logic flow in acpi_processor_errata_piix4().
 * Triggering this requires specific hardware or kernel emulation.
 */

#include <linux/acpi.h>
#include <linux/device.h>

// Vulnerable function simulation
void vulnerable_acpi_processor_errata_piix4(struct device *dev) {
    // ... some logic ...

    // 1. Drop reference to the device object
    put_device(dev);

    // 2. Use-after-free: Dereferencing the pointer after dropping the reference
    // This is the vulnerable part described in the CVE.
    if (dev->kobj.sd) {
        printk(KERN_DEBUG "Device still exists (UAF trigger)");
    }
}

/*
 * Exploitation Logic:
 * 1. Attacker gains local access (PR:L).
 * 2. Attacker triggers ACPI processor enumeration/scan.
 * 3. Kernel executes the vulnerable path, causing a race or crash.
 */

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-23443
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-23443
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-23443/
[4] VulDB https://vuldb.com/cve/CVE-2026-23443
[5] https://git.kernel.org/stable/c/2e369ba9eb7b8a06e9cc35a3e7fe73e59272f8c2
[6] https://git.kernel.org/stable/c/68408e8f9e366ad9850a66ac65cb569f13bf6cd4
[7] https://git.kernel.org/stable/c/8583f62259e1b315d5239371adfb36939cdab741
[8] https://git.kernel.org/stable/c/98473309a36acc271009b85e0bb53a4c0dddf5c2
[9] https://git.kernel.org/stable/c/bf504b229cb8d534eccbaeaa23eba34c05131e25
[10] https://git.kernel.org/stable/c/e0c470049344e9346fff79d7e2362212c216665e
[11] https://git.kernel.org/stable/c/edf4c2aaee08e8fd503fbae705c801e92a0b55d7

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-23443", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-03T16:16:28.573", "lastModified": "2026-04-23T20:58:48.307", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nACPI: processor: Fix previous acpi_processor_errata_piix4() fix\n\nAfter commi f132e089fe89 (\"ACPI: processor: Fix NULL-pointer dereference\nin acpi_processor_errata_piix4()\"), device pointers may be dereferenced\nafter dropping references to the device objects pointed to by them,\nwhich may cause a use-after-free to occur.\n\nMoreover, debug messages about enabling the errata may be printed\nif the errata flags corresponding to them are unset.\n\nAddress all of these issues by moving message printing to the points\nin the code where the errata flags are set."}], "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": "6.1.165", "versionEndExcluding": "6.1.167", "matchCriteriaId": "D54E2FD5-7EF9-426A-9AE1-8E8DA970BCC8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.128", "versionEndExcluding": "6.6.130", "matchCriteriaId": "2099D3D0-97C6-44C5-913D-E616B07A9237"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.75", "versionEndExcluding": "6.12.78", "matchCriteriaId": "DAB9F88E-FB55-4FDB-966E-E7FC262B2038"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.16", "versionEndExcluding": "6.18.20", "matchCriteriaId": "234D2F07-A17A-49BE-8B89-9C6756315A38"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19.6", "versionEndExcluding": "6.19.10", "matchCriteriaId": "20A592B7-9A05-4B02-A583-F1B95CD93223"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:5.15.202:*:*:*:*:*:*:*", "matchCriteriaId": "822A7BB5-FF38-425A-B8A8-9F102CF92C36"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/2e369ba9eb7b8a06e9cc35a3e7fe73e59272f8c2", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/68408e8f9e366ad9850a66ac65cb569f13bf6cd4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/8583f62259e1b315d5239371adfb36939cdab741", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/98473309a36acc271009b85e0bb53a4c0dddf5c2", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/bf504b229cb8d534eccbaeaa23eba34c05131e25", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/e0c470049344e9346fff79d7e2362212c216665e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/edf4c2aaee08e8fd503fbae705c801e92a0b55d7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}