CVE-2026-74507

medium

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: HIDP: validate numbered report payloads When hidp_get_raw_report() waits for a numbered report, hidp_process_data() compares the expected report number with skb->data[0]. A connected HIDP peer can reply with only a DATA transaction header, leaving the skb empty after the header is removed. KMSAN reports an uninitialized-value use in hidp_session_run(), with the value originating in __alloc_skb() through vhci_write(). The transaction header checks remove the empty-frame reports, but this report remains until the payload check is added. The comparison can also consume a peer-controlled byte beyond the declared L2CAP PDU. A DATA | FEATURE response followed by an extra 0x01 byte made the current code accept that byte as report ID 1 and complete HIDIOCGFEATURE with a zero-byte result. With this change the malformed response is rejected with -EIO, while a subsequent valid response still succeeds. Require a payload byte before comparing a numbered report ID. Unnumbered reports continue to accept an empty payload.