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CVE-2026-46123— Bluetooth: virtio_bt: clamp rx length before skb_put

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于Bluetooth virtio_bt中未对rx长度进行钳制，可能导致使用未初始化内核堆字节。

CVSS 7.7 · High EPSS 0.14% · P3

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 19

VendorProduct Version RangeStatus
Linux Linux cf2719a21fdb9d4c8e9c834d279163609bef575d< 4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a affected
160fbcf3bfb93c3c086427f9f4c8bc70f217e9be< fd91fa2678ab603dfb285416c1cf3843d7be1e41 affected
160fbcf3bfb93c3c086427f9f4c8bc70f217e9be< ed41c81d30b211a671667259c3b5feeba0e062d5 affected
160fbcf3bfb93c3c086427f9f4c8bc70f217e9be< 6c1730099a6fc18b183bd6c1adad3b54adcaeda9 affected
160fbcf3bfb93c3c086427f9f4c8bc70f217e9be< b40cdd1b1370d76e9e760af4490cb4a351cceead affected
160fbcf3bfb93c3c086427f9f4c8bc70f217e9be< e6b4296f170d949ebba937cf6a3f247ec9550d2c affected
160fbcf3bfb93c3c086427f9f4c8bc70f217e9be< 21bd244b6de5d2fe1063c23acc93fbdd2b20d112 affected
9b67438e315b925a699f0178f4a48baf3d2d6ef4 affected
… +11 more rows
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I. Basic Information for CVE-2026-46123

Vulnerability Information
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Vulnerability Title
Bluetooth: virtio_bt: clamp rx length before skb_put
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: virtio_bt: clamp rx length before skb_put virtbt_rx_work() calls skb_put(skb, len) where len comes directly from virtqueue_get_buf() with no validation against the buffer we posted to the device. The RX skb is allocated in virtbt_add_inbuf() and exposed to virtio as exactly 1000 bytes via sg_init_one(). Checking len against skb_tailroom(skb) is not sufficient because alloc_skb() can leave more tailroom than the 1000 bytes actually handed to the device. A malicious or buggy backend can therefore report used.len between 1001 and skb_tailroom(skb), causing skb_put() to include uninitialized kernel heap bytes that were never written by the device. The same path also accepts len == 0, in which case skb_put(skb, 0) leaves the skb empty but virtbt_rx_handle() still reads the pkt_type byte from skb->data, consuming uninitialized memory. Define VIRTBT_RX_BUF_SIZE once and reuse it in alloc_skb() and sg_init_one(), and gate virtbt_rx_work() on that same constant so the bound checked matches the buffer actually exposed to the device. Reject used.len == 0 in the same gate so an empty completion can no longer reach virtbt_rx_handle(). Use bt_dev_err_ratelimited() because the length value comes from an untrusted backend that can otherwise flood the kernel log. Same class of bug as commit c04db81cd028 ("net/9p: Fix buffer overflow in USB transport layer"), which hardened the USB 9p transport against unchecked device-reported length.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于Bluetooth virtio_bt中未对rx长度进行钳制，可能导致使用未初始化内核堆字节。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux cf2719a21fdb9d4c8e9c834d279163609bef575d ~ 4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a -
Linux Linux 6.1 -

II. Public POCs for CVE-2026-46123

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III. Intelligence Information for CVE-2026-46123

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Patches & Fixes for CVE-2026-46123 (7)

Same Patch Batch · Linux · 2026-05-28 · 135 CVEs total

CVE-2026-46135 9.8 CRITICAL nvmet-tcp: fix race between ICReq handling and queue teardown
CVE-2026-46195 9.8 CRITICAL smb: client: validate dacloffset before building DACL pointers
CVE-2026-46137 9.8 CRITICAL mptcp: pm: ADD_ADDR rtx: fix potential data-race
CVE-2026-46115 9.8 CRITICAL block: add pgmap check to biovec_phys_mergeable
CVE-2026-46155 9.1 CRITICAL smb/client: fix out-of-bounds read in smb2_compound_op()
CVE-2026-46119 9.1 CRITICAL libceph: Fix slab-out-of-bounds access in auth message processing
CVE-2026-46185 9.1 CRITICAL smb/client: fix out-of-bounds read in symlink_data()
CVE-2026-46212 8.8 HIGH batman-adv: bla: prevent use-after-free when deleting claims
CVE-2026-46174 8.8 HIGH x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache
CVE-2026-46125 8.8 HIGH wifi: mac80211: remove station if connection prep fails
CVE-2026-46198 8.8 HIGH batman-adv: fix integer overflow on buff_pos
CVE-2026-46166 8.8 HIGH wifi: mac80211: use safe list iteration in radar detect work
CVE-2026-46152 8.8 HIGH wifi: mac80211: drop stray 'static' from fast-RX rx_result
CVE-2026-46238 8.8 HIGH batman-adv: stop caching unowned originator pointers in BAT IV
CVE-2026-46113 8.8 HIGH KVM: x86: Fix shadow paging use-after-free due to unexpected GFN
CVE-2026-46232 8.1 HIGH HID: playstation: Clamp num_touch_reports
CVE-2026-46138 8.1 HIGH Bluetooth: hci_event: Fix OOB read and infinite loop in hci_le_create_big_complete_evt
CVE-2026-46215 7.8 HIGH drm: Set old handle to NULL before prime swap in change_handle
CVE-2026-46201 7.8 HIGH drm/xe: Fix dma-buf attachment leak in xe_gem_prime_import()
CVE-2026-46157 7.8 HIGH ALSA: pcm: oss: Fix data race at accessing runtime.oss.trigger

Showing top 20 of 135 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-46123

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