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CVE Record

CVE-2024-36968: Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init() l2cap_le_flowctl_init() can cause both div-by-zero and an integer overflow since hdev->le_mtu may not fall in the valid range. Move MTU from hci_dev to hci_conn to validate MTU and stop the connection process earlier if MTU is invalid. Also, add a missing validation in read_buffer_size() and make it return an error value if the validation fails. Now hci_conn_add() returns ERR_PTR() as it can fail due to the both a kzalloc failure and invalid MTU value. divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G W 6.9.0-rc5+ #20 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: hci0 hci_rx_work RIP: 0010:l2cap_le_flowctl_init+0x19e/0x3f0 net/bluetooth/l2cap_core.c:547 Code: e8 17 17 0c 00 66 41 89 9f 84 00 00 00 bf 01 00 00 00 41 b8 02 00 00 00 4c 89 fe 4c 89 e2 89 d9 e8 27 17 0c 00 44 89 f0 31 d2 <66> f7 f3 89 c3 ff c3 4d 8d b7 88 00 00 00 4c 89 f0 48 c1 e8 03 42 RSP: 0018:ffff88810bc0f858 EFLAGS: 00010246 RAX: 00000000000002a0 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffff88810bc0f7c0 RDI: ffffc90002dcb66f RBP: ffff88810bc0f880 R08: aa69db2dda70ff01 R09: 0000ffaaaaaaaaaa R10: 0084000000ffaaaa R11: 0000000000000000 R12: ffff88810d65a084 R13: dffffc0000000000 R14: 00000000000002a0 R15: ffff88810d65a000 FS: 0000000000000000(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000100 CR3: 0000000103268003 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <TASK> l2cap_le_connect_req net/bluetooth/l2cap_core.c:4902 [inline] l2cap_le_sig_cmd net/bluetooth/l2cap_core.c:5420 [inline] l2cap_le_sig_channel net/bluetooth/l2cap_core.c:5486 [inline] l2cap_recv_frame+0xe59d/0x11710 net/bluetooth/l2cap_core.c:6809 l2cap_recv_acldata+0x544/0x10a0 net/bluetooth/l2cap_core.c:7506 hci_acldata_packet net/bluetooth/hci_core.c:3939 [inline] hci_rx_work+0x5e5/0xb20 net/bluetooth/hci_core.c:4176 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335 worker_thread+0x926/0xe70 kernel/workqueue.c:3416 kthread+0x2e3/0x380 kernel/kthread.c:388 ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]---

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2024-36968 is a Linux kernel Bluetooth flaw that can crash vulnerable systems during Bluetooth LE L2CAP connection handling. The bug is caused by invalid MTU values leading to divide-by-zero and possible integer overflow. Business urgency depends on whether affected Linux systems use Bluetooth and have kernel fixes applied.

Executive priority

Moderate operational priority where Bluetooth is enabled, but final urgency is constrained by missing severity scoring and exploit evidence. Patch through normal kernel maintenance, accelerating for endpoints or embedded systems with active Bluetooth use.

Technical view

The issue is in l2cap_le_flowctl_init() in the Linux kernel Bluetooth L2CAP path. hdev->le_mtu may be outside the valid range, allowing divide-by-zero and integer overflow. The fix moves MTU handling to hci_conn, validates earlier, adds read_buffer_size() validation, and lets hci_conn_add() fail on invalid MTU.

Likely exposure

Exposure is most relevant to Linux systems running affected kernel versions with Bluetooth LE/L2CAP functionality enabled or reachable. The provided data identifies Linux as affected but does not provide distribution-specific package names, CVSS scoring, or deployment prevalence.

Exploitation context

The source bundle shows a kernel crash trace and no CISA KEV listing. It does not cite active exploitation, public exploit availability, remote prerequisites, or authentication requirements. Treat exploitation status as unconfirmed from the provided evidence.

Researcher notes

Do not assume exploitability beyond the provided crash evidence. The key validation target is whether kernel builds contain the stable commits fixing MTU validation and connection failure behavior. Distribution backports may not match upstream version numbers exactly.

Mitigation direction

  • Apply Linux kernel updates that include the referenced stable fixes.
  • Check your distribution advisory for the exact fixed kernel package.
  • Prioritize systems where Bluetooth LE is enabled or operationally exposed.
  • If patching is delayed, follow vendor guidance for compensating controls.

Validation and detection

  • Inventory Linux kernel versions across laptops, servers, appliances, and embedded systems.
  • Confirm whether Bluetooth and Bluetooth LE support are enabled on each asset.
  • Map installed kernels to distribution advisories or the referenced stable commits.
  • Verify patched systems no longer run affected kernel builds.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2024-36968 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux6ed58ec520ad2b2fe3f955c8a5fd0eecafccebdf, 6ed58ec520ad2b2fe3f955c8a5fd0eecafccebdf, 6ed58ec520ad2b2fe3f955c8a5fd0eecafccebdf, 6ed58ec520ad2b2fe3f955c8a5fd0eecafccebdf, 6ed58ec520ad2b2fe3f955c8a5fd0eecafccebdfunaffected
LinuxLinux2.6.39, 0, 6.6.32, 6.8.11, 6.9.2, 6.9.4, 6.10affected
Weakness

CWE details

No CWE listed

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