CVE-2026-64427CVE-2026-64427

In 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: B