GHSA-M6MF-CRM7-82WQ
Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31In the Linux kernel, the following vulnerability has been resolved:
HID: logitech-dj: Fix maxfield check in DJ short report validation
Commit b6a57912854e ("HID: logitech-dj: Prevent REPORT_ID_DJ_SHORT related user initiated OOB write") added validation for the DJ short output report, but the error path dereferences rep->field[0] even when rep->maxfield is zero.
Commit 8b9a097eb2fc ("HID: logitech-dj: fix wrong detection of bad DJ_SHORT output report") made the check conditional on rep being present, but a crafted descriptor can still create report ID 0x20 with only padding output items. hid-core registers the report, ignores the padding field, and leaves rep->maxfield as zero.
In that case the validation enters the rep->maxfield < 1 branch and then dereferences rep->field[0]->report_count while printing the error message, causing a NULL pointer dereference during probe. This is reproducible with uhid by emulating a Logitech receiver with a padding-only DJ short output report:
BUG: KASAN: null-ptr-deref in logi_dj_probe+0xb1/0x754 [hid_logitech_dj] Read of size 4 at addr 0000000000000028 by task kworker/4:1/129 ... Call Trace: logi_dj_probe+0xb1/0x754 [hid_logitech_dj] hid_device_probe+0x329/0x3f0 [hid] really_probe+0x162/0x570 __device_attach+0x137/0x2c0 bus_probe_device+0x38/0xc0 device_add+0xa56/0xce0 hid_add_device+0x19c/0x280 [hid] uhid_device_add_worker+0x2c/0xb0 [uhid]
Reject the zero-field report before printing the field report_count.
{
"affected": [],
"aliases": [
"CVE-2026-64427"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-25T10:17:26Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nHID: logitech-dj: Fix maxfield check in DJ short report validation\n\nCommit b6a57912854e (\"HID: logitech-dj: Prevent REPORT_ID_DJ_SHORT\nrelated user initiated OOB write\") added validation for the DJ short\noutput report, but the error path dereferences rep-\u003efield[0] even when\nrep-\u003emaxfield is zero.\n\nCommit 8b9a097eb2fc (\"HID: logitech-dj: fix wrong detection of bad\nDJ_SHORT output report\") made the check conditional on rep being present,\nbut a crafted descriptor can still create report ID 0x20 with only padding\noutput items. hid-core registers the report, ignores the padding field,\nand leaves rep-\u003emaxfield as zero.\n\nIn that case the validation enters the rep-\u003emaxfield \u003c 1 branch and then\ndereferences rep-\u003efield[0]-\u003ereport_count while printing the error message,\ncausing a NULL pointer dereference during probe. This is reproducible with\nuhid by emulating a Logitech receiver with a padding-only DJ short output\nreport:\n\n BUG: KASAN: null-ptr-deref in logi_dj_probe+0xb1/0x754 [hid_logitech_dj]\n Read of size 4 at addr 0000000000000028 by task kworker/4:1/129\n ...\n Call Trace:\n logi_dj_probe+0xb1/0x754 [hid_logitech_dj]\n hid_device_probe+0x329/0x3f0 [hid]\n really_probe+0x162/0x570\n __device_attach+0x137/0x2c0\n bus_probe_device+0x38/0xc0\n device_add+0xa56/0xce0\n hid_add_device+0x19c/0x280 [hid]\n uhid_device_add_worker+0x2c/0xb0 [uhid]\n\nReject the zero-field report before printing the field report_count.",
"id": "GHSA-m6mf-crm7-82wq",
"modified": "2026-07-25T12:31:35Z",
"published": "2026-07-25T12:31:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64427"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/590cc4d782487632a52f37c2171bee1eeea29627"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7a89ad762fad53d56b7002d7ffc923a4b7f4006f"
}
],
"schema_version": "1.4.0",
"severity": []
}
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