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CVE-2022-49908

Bluetooth: L2CAP: Fix memory leak in vhci_write

Medium5.5EPSS 0.20%
Published
Updated
Reserved
Assigned by
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix memory leak in vhci_write Syzkaller reports a memory leak as follows: ==================================== BUG: memory leak unreferenced object 0xffff88810d81ac00 (size 240): [...] hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418 [<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline] [<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline] [<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline] [<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511 [<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline] [<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline] [<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578 [<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631 [<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd ==================================== HCI core will uses hci_rx_work() to process frame, which is queued to the hdev->rx_q tail in hci_recv_frame() by HCI driver. Yet the problem is that, HCI core may not free the skb after handling ACL data packets. To be more specific, when start fragment does not contain the L2CAP length, HCI core just copies skb into conn->rx_skb and finishes frame process in l2cap_recv_acldata(), without freeing the skb, which triggers the above memory leak. This patch solves it by releasing the relative skb, after processing the above case in l2cap_recv_acldata().

Timeline

  1. ID reserved

    By Linux

  2. Published

  3. · 13 months later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2022-49908, by who scored it
Scored byCVSSScoreVector
CISA-ADPADP (enrichment)3.1Medium5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVDNVD · Modified3.1Medium5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
0.20% · top 90% of all CVEs (7 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: no · Technical impact: partial
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.

Weakness

Affected products

  • Linux · Linux

    • affected 4d7ea8ee90e42fc75995f6fb24032d3233314528 – < aa16cac06b752e5f609c106735bd7838f444784c
    • affected 4d7ea8ee90e42fc75995f6fb24032d3233314528 – < 5b4f039a2f487c5edae681d763fe1af505f84c13
    • affected 4d7ea8ee90e42fc75995f6fb24032d3233314528 – < 7c9524d929648935bac2bbb4c20437df8f9c3f42

  • Linux · Linux

    • affected 5.12
    • unaffected < 5.12
    • unaffected 5.15.78 – ≤ 5.15.*
    • unaffected 6.0.8 – ≤ 6.0.*
    • unaffected 6.1 – ≤ *

References (3)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .