{
  "cveId": "CVE-2023-52894",
  "url": "https://patchblox.com/security/cve/CVE-2023-52894",
  "summary": "CVE-2023-52894 is fixed in linux on 1 platform, first by DEBIAN-CVE-2023-52894, released August 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  usb: gadget: f_ncm: fix potential NULL ptr deref...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  usb: gadget: f_ncm: fix potential NULL ptr deref in ncm_bitrate()  In Google internal bug 265639009 we\u0027ve received an (as yet) unreproducible crash report from an aarch64 GKI 5.10.149-android13 running device.  AFAICT the source code is at:   https://android.googlesource.com/kernel/common/\u002B/refs/tags/ASB-2022-12-05_13-5.10  The call stack is:   ncm_close() -\u003E ncm_notify() -\u003E ncm_do_notify() with the crash at:   ncm_do_notify\u002B0x98/0x270 Code: 79000d0b b9000a6c f940012a f9400269 (b9405d4b)  Which I believe disassembles to (I don\u0027t know ARM assembly, but it looks sane enough to me...):    // halfword (16-bit) store presumably to event-\u003EwLength (at offset 6 of struct usb_cdc_notification)   0B 0D 00 79    strh w11, [x8, #6]    // word (32-bit) store presumably to req-\u003ELength (at offset 8 of struct usb_request)   6C 0A 00 B9    str  w12, [x19, #8]    // x10 (NULL) was read here from offset 0 of valid pointer x9   // IMHO we\u0027re reading \u0027cdev-\u003Egadget\u0027 and getting NULL   // gadget is indeed at offset 0 of struct usb_composite_dev   2A 01 40 F9    ldr  x10, [x9]    // loading req-\u003Ebuf pointer, which is at offset 0 of struct usb_request   69 02 40 F9    ldr  x9, [x19]    // x10 is null, crash, appears to be attempt to read cdev-\u003Egadget-\u003Emax_speed   4B 5D 40 B9    ldr  w11, [x10, #0x5c]  which seems to line up with ncm_do_notify() case NCM_NOTIFY_SPEED code fragment:    event-\u003EwLength = cpu_to_le16(8);   req-\u003Elength = NCM_STATUS_BYTECOUNT;    /* SPEED_CHANGE data is up/down speeds in bits/sec */   data = req-\u003Ebuf \u002B sizeof *event;   data[0] = cpu_to_le32(ncm_bitrate(cdev-\u003Egadget));  My analysis of registers and NULL ptr deref crash offset   (Unable to handle kernel NULL pointer dereference at virtual address 000000000000005c) heavily suggests that the crash is due to \u0027cdev-\u003Egadget\u0027 being NULL when executing:   data[0] = cpu_to_le32(ncm_bitrate(cdev-\u003Egadget)); which calls:   ncm_bitrate(NULL) which then calls:   gadget_is_superspeed(NULL) which reads   ((struct usb_gadget *)NULL)-\u003Emax_speed and hits a panic.  AFAICT, if I\u0027m counting right, the offset of max_speed is indeed 0x5C. (remember there\u0027s a GKI KABI reservation of 16 bytes in struct work_struct)  It\u0027s not at all clear to me how this is all supposed to work... but returning 0 seems much better than panic-ing...",
  "published": "2024-08-21T07:15:05Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00243,
  "epssPercentile": 0.15522,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.1.8-1",
      "fix": "DEBIAN-CVE-2023-52894",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-52894",
      "released": "2024-08-21T07:15:05Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.1.8-1",
      "fix": "DEBIAN-CVE-2023-52894",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-52894",
      "released": "2024-08-21T07:15:05Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "6.1.8-1",
      "fix": "DEBIAN-CVE-2023-52894",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-52894",
      "released": "2024-08-21T07:15:05Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}