UnratedFix available

Bluetooth: RFCOMM: Reject short EA=0 frames in rfcomm_recv_frame()

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: Reject short EA=0 frames in rfcomm_recv_frame() While rfcomm_recv_frame() verifies that skb->len is at least sizeof(*hdr) + 1 (4 bytes: 3-byte header + 1-byte FCS), an RFCOMM frame with an extended 2-byte length field (!__test_ea(hdr->len)) has a 4-byte header plus a 1-byte FCS (5 bytes minimum, sizeof(*hdr) + 2). When a 4-byte RFCOMM frame with EA == 0 arrives: 1. The initial skb->len < sizeof(*hdr) + 1 check passes (4 < 4 is false). 2. Trimming the FCS byte decrements skb->len to 3. 3. If __check_fcs() succeeds, skb_pull(skb, 4) fails (4 > 3) and returns NULL without advancing skb->data. 4. Because the return value of skb_pull() is ignored, the un-pulled 3-byte struct rfcomm_hdr remains at skb->data and is either queued as application payload via rfcomm_recv_data() or parsed as a multiplexer control command via rfcomm_recv_mcc() on DLCI 0. Fix this by extending the length check in rfcomm_recv_frame() to also require skb->len >= sizeof(*hdr) + 2 when !__test_ea(hdr->len).

Products: Kernel
Affected versions: Not specified
Fixed versions: 6.12.112, 6.18.55, 7.2.9
CVEs: CVE-2026-98600
Confirmed fixed CVEs: Not specified
Updated in this feed: 4 Nov 2026, 04:00 UTC · Revision 1

Source evidence

Bluetooth: RFCOMM: Reject short EA=0 frames in rfcomm_recv_frame()

core-osv · Original source

Published 18 Oct 2026, 15:19 UTC

osv:CVE-2026-98600

Kernel

Fixed versions: 6.12.112, 6.18.55, 7.2.9

Complete source record

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  "url": "https://osv.dev/vulnerability/CVE-2026-98600",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Bluetooth: RFCOMM: Reject short EA=0 frames in rfcomm_recv_frame()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: Reject short EA=0 frames in rfcomm_recv_frame() While rfcomm_recv_frame() verifies that skb->len is at least sizeof(*hdr) + 1 (4 bytes: 3-byte header + 1-byte FCS), an RFCOMM frame with an extended 2-byte length field (!__test_ea(hdr->len)) has a 4-byte header plus a 1-byte FCS (5 bytes minimum, sizeof(*hdr) + 2). When a 4-byte RFCOMM frame with EA == 0 arrives: 1. The initial skb->len < sizeof(*hdr) + 1 check passes (4 < 4 is false). 2. Trimming the FCS byte decrements skb->len to 3. 3. If __check_fcs() succeeds, skb_pull(skb, 4) fails (4 > 3) and returns NULL without advancing skb->data. 4. Because the return value of skb_pull() is ignored, the un-pulled 3-byte struct rfcomm_hdr remains at skb->data and is either queued as application payload via rfcomm_recv_data() or parsed as a multiplexer control command via rfcomm_recv_mcc() on DLCI 0. Fix this by extending the length check in rfcomm_recv_frame() to also require skb->len >= sizeof(*hdr) + 2 when !__test_ea(hdr->len).",
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      "modified": "2026-10-28T02:30:33.025720533Z",
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  "source_id": "core-osv",
  "document_id": 500199,
  "published_at": "2026-10-18T15:19:12.864+00:00"
}