{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-52856",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2023-52856"
  ],
  "published": "2024-05-21T15:34:20Z",
  "summary": "drm/bridge: lt8912b: Fix crash on bridge detach",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/bridge: lt8912b: Fix crash on bridge detach\n\nThe lt8912b driver, in its bridge detach function, calls\ndrm_connector_unregister() and drm_connector_cleanup().\n\ndrm_connector_unregister() should be called only for connectors\nexplicitly registered with drm_connector_register(), which is not the\ncase in lt8912b.\n\nThe driver's drm_connector_funcs.destroy hook is set to\ndrm_connector_cleanup().\n\nThus the driver should not call either drm_connector_unregister() nor\ndrm_connector_cleanup() in its lt8912_bridge_detach(), as they cause a\ncrash on bridge detach:\n\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000000\nMem abort info:\n  ESR = 0x0000000096000006\n  EC = 0x25: DABT (current EL), IL = 32 bits\n  SET = 0, FnV = 0\n  EA = 0, S1PTW = 0\n  FSC = 0x06: level 2 translation fault\nData abort info:\n  ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000\n  CM = 0, WnR = 0, TnD = 0, TagAccess = 0\n  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0\nuser pgtable: 4k pages, 48-bit VAs, pgdp=00000000858f3000\n[0000000000000000] pgd=0800000085918003, p4d=0800000085918003, pud=0800000085431003, pmd=0000000000000000\nInternal error: Oops: 0000000096000006 [#1] PREEMPT SMP\nModules linked in: tidss(-) display_connector lontium_lt8912b tc358768 panel_lvds panel_simple drm_dma_helper drm_kms_helper drm drm_panel_orientation_quirks\nCPU: 3 PID: 462 Comm: rmmod Tainted: G        W          6.5.0-rc2+ #2\nHardware name: Toradex Verdin AM62 on Verdin Development Board (DT)\npstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : drm_connector_cleanup+0x78/0x2d4 [drm]\nlr : lt8912_bridge_detach+0x54/0x6c [lontium_lt8912b]\nsp : ffff800082ed3a90\nx29: ffff800082ed3a90 x28: ffff0000040c1940 x27: 0000000000000000\nx26: 0000000000000000 x25: dead000000000122 x24: dead000000000122\nx23: dead000000000100 x22: ffff000003fb6388 x21: 0000000000000000\nx20: 0000000000000000 x19: ffff000003fb6260 x18: fffffffffffe56e8\nx17: 0000000000000000 x16: 0010000000000000 x15: 0000000000000038\nx14: 0000000000000000 x13: ffff800081914b48 x12: 000000000000040e\nx11: 000000000000015a x10: ffff80008196ebb8 x9 : ffff800081914b48\nx8 : 00000000ffffefff x7 : ffff0000040c1940 x6 : ffff80007aa649d0\nx5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008159e008\nx2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000\nCall trace:\n drm_connector_cleanup+0x78/0x2d4 [drm]\n lt8912_bridge_detach+0x54/0x6c [lontium_lt8912b]\n drm_bridge_detach+0x44/0x84 [drm]\n drm_encoder_cleanup+0x40/0xb8 [drm]\n drmm_encoder_alloc_release+0x1c/0x30 [drm]\n drm_managed_release+0xac/0x148 [drm]\n drm_dev_put.part.0+0x88/0xb8 [drm]\n devm_drm_dev_init_release+0x14/0x24 [drm]\n devm_action_release+0x14/0x20\n release_nodes+0x5c/0x90\n devres_release_all+0x8c/0xe0\n device_unbind_cleanup+0x18/0x68\n device_release_driver_internal+0x208/0x23c\n driver_detach+0x4c/0x94\n bus_remove_driver+0x70/0xf4\n driver_unregister+0x30/0x60\n platform_driver_unregister+0x14/0x20\n tidss_platform_driver_exit+0x18/0xb2c [tidss]\n __arm64_sys_delete_module+0x1a0/0x2b4\n invoke_syscall+0x48/0x110\n el0_svc_common.constprop.0+0x60/0x10c\n do_el0_svc_compat+0x1c/0x40\n el0_svc_compat+0x40/0xac\n el0t_32_sync_handler+0xb0/0x138\n el0t_32_sync+0x194/0x198\nCode: 9104a276 f2fbd5b7 aa0203e1 91008af8 (f85c0420)",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.63",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-52856"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/42071feab712ba2a139b8928f7e0f8d3a6fc719e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7bf0cb8f40280a85034990dfe42be8ca8f80f37a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fcd9895e365474709844eeb31cfe53d912c3596e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b65e3249f3ca96e3c736af889461d80d675feab6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/44283993144a03af9df31934d6c32bbd42d1a347"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}