GHSA-84X9-CXQ8-HPGQ
Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32In the Linux kernel, the following vulnerability has been resolved:
HID: picolcd: clamp eeprom debugfs read to bytes actually received
picolcd_debug_eeprom_read() trusts resp->raw_data[2] -- a length byte supplied by the device in its REPORT_EE_DATA reply -- clamped only to the caller's read() count:
ret = resp->raw_data[2];
if (ret > s)
ret = s;
if (copy_to_user(u, resp->raw_data+3, ret))
It never checks resp->raw_size, the number of bytes picolcd_raw_event() actually copied into the 64-byte raw_data[] of the kmalloc'd struct picolcd_pending. A device (or a spoofed picoLCD) returning a length byte of 0xff, read with a count >= 255, makes copy_to_user() read past raw_data[] into adjacent slab memory and return it to userspace through the debugfs "eeprom" file:
BUG: KASAN: slab-out-of-bounds in _copy_to_user
Read of size 255 ... picolcd_debug_eeprom_read+0x214/0x2f0 [hid_picolcd]
The debug-dump path in the same file already validates the device length byte against the received size before trusting it; this read does not. The file is created S_IRUSR (root-only) and a crafted device is needed, so it is neither unprivileged- nor remotely-triggerable.
Clamp the copy length to resp->raw_size - 3 (the payload actually received, minus the 3-byte header), floored at 0 for short replies.
{
"affected": [],
"aliases": [
"CVE-2026-89628"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-11T20:19:48Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nHID: picolcd: clamp eeprom debugfs read to bytes actually received\n\npicolcd_debug_eeprom_read() trusts resp-\u003eraw_data[2] -- a length byte\nsupplied by the device in its REPORT_EE_DATA reply -- clamped only to\nthe caller\u0027s read() count:\n\n\tret = resp-\u003eraw_data[2];\n\tif (ret \u003e s)\n\t\tret = s;\n\tif (copy_to_user(u, resp-\u003eraw_data+3, ret))\n\nIt never checks resp-\u003eraw_size, the number of bytes picolcd_raw_event()\nactually copied into the 64-byte raw_data[] of the kmalloc\u0027d struct\npicolcd_pending. A device (or a spoofed picoLCD) returning a length byte\nof 0xff, read with a count \u003e= 255, makes copy_to_user() read past\nraw_data[] into adjacent slab memory and return it to userspace through\nthe debugfs \"eeprom\" file:\n\n\tBUG: KASAN: slab-out-of-bounds in _copy_to_user\n\tRead of size 255 ... picolcd_debug_eeprom_read+0x214/0x2f0 [hid_picolcd]\n\nThe debug-dump path in the same file already validates the device length\nbyte against the received size before trusting it; this read does not.\nThe file is created S_IRUSR (root-only) and a crafted device is needed,\nso it is neither unprivileged- nor remotely-triggerable.\n\nClamp the copy length to resp-\u003eraw_size - 3 (the payload actually\nreceived, minus the 3-byte header), floored at 0 for short replies.",
"id": "GHSA-84x9-cxq8-hpgq",
"modified": "2026-09-14T15:32:33Z",
"published": "2026-09-11T21:31:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89628"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1a02056c2bf7ef9b5fd05ee6913aeeadb703c443"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/471f4a939c66d1d44aece2321807abf609fc9098"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4daf432c94a42e7be6aa10b012b33af5ed9bc118"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/65daa322f1021d8206f8032c4cd4c0cb2d26c7c3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/699a3c8b56e168ca19d12722f3f5ef1d6f4b1d84"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8dc662af019158690c470edd2e2857657f700abb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a3e6e8d7198a9f3861861520a38b673684a1062b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e9c667395ac1f8024f623250b32bae4c7af9caa0"
}
],
"schema_version": "1.4.0",
"severity": []
}
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