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CVE-2026-93783

Bluetooth: RFCOMM: validate skb length in rfcomm_recv_frame PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: validate skb length in rfcomm_recv_frame rfcomm_recv_frame() casts skb->data to struct rfcomm_hdr and dereferences hdr->addr and hdr->ctrl without validating skb->len first. A truncated frame with skb->len less than the minimum header size causes an out-of-bounds read of uninitialized memory. Additionally, a zero-length frame causes skb->len-- to underflow to UINT_MAX, making skb_tail_pointer() read far past the buffer. Commit 23882b828c3c ("Bluetooth: RFCOMM: validate skb length in MCC handlers") fixed the same class of missing-length-check bugs in the MCC sub-handlers, but the top-level rfcomm_recv_frame() was left unfixed. KMSAN reports: BUG: KMSAN: uninit-value in rfcomm_run ... Uninit was created at: __alloc_skb+0x474/0xb60 vhci_write+0xe9/0x870 Fix this by rejecting frames smaller than sizeof(struct rfcomm_hdr) + 1 (the minimum frame must have a 3-byte header and a 1-byte FCS).

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before fb40eda15122f6b780228639c1ead6820340ff54; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 3829af5fab5a22405bf1e7d69068c2ec0fce46ca; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before b161eacd7fa4a2d765724b5504ac6cc388e48f80; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 30d1d9f3495463f7c026e4c553127f79b486fcd6; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 67dc3b40fae71b6b11c71e7ff69bac0758818c05; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before bbc310caa2b6bf5fe42896ba27da0fbc12e4ac51; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before b230e5bf501c5edaf2eb0991cb862ac142031d4b
Linux / Linuxaffected 2.6.12; unaffected 0 before 2.6.12; unaffected 5.10.271 through 5.10.*; unaffected 5.15.222 through 5.15.*; unaffected 6.1.189 through 6.1.*; unaffected 6.6.158 through 6.6.*; unaffected 6.12.111 through 6.12.*; unaffected 6.18.53 through 6.18.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References