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CVE-2026-46275— Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths

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，该漏洞源于蓝牙hci_uart的关闭和初始化路径中存在释放后重用和竞争条件，可能导致空指针取消引用。

CVSS 7.8 · High EPSS 0.19% · P8

Affected Version Matrix 28

VendorProduct Version RangeStatus
Linux Linux 3b799254cf6f481460719023d7a18f46651e5e7f< 78aad93e938f013d9272fe0ee168f27883afa95c affected
3b799254cf6f481460719023d7a18f46651e5e7f< e2d19969c8d9198ecc3090bcd5312ecd503a3339 affected
3b799254cf6f481460719023d7a18f46651e5e7f< c85cff648a2bc92322912db5f1727ad05afae7b6 affected
3b799254cf6f481460719023d7a18f46651e5e7f< 9d20d48be2c4a071fb015eb09bda2cecd25daf34 affected
3b799254cf6f481460719023d7a18f46651e5e7f< 81c7a3c22a0f2808cf4ae0b4908f59763b23606d affected
3b799254cf6f481460719023d7a18f46651e5e7f< 192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894 affected
3b799254cf6f481460719023d7a18f46651e5e7f< 7338031946bd06f6dff149e67b60c4cd083bfea8 affected
3b799254cf6f481460719023d7a18f46651e5e7f< c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b affected
… +20 more rows
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I. Basic Information for CVE-2026-46275

Vulnerability Information
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Vulnerability Title
Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths Vulnerabilities leading to Use-After-Free (UAF) and Null Pointer Dereference (NPD) conditions were observed in the lifecycle management of hci_uart. The primary issue arises because the workqueues (init_ready and write_work) are only flushed/cancelled if the HCI_UART_PROTO_READY flag is set during TTY close. If a hangup occurs before setup completes, hci_uart_tty_close() skips the teardown of these workqueues and proceeds to free the `hu` struct. When the scheduled work executes later, it blindly dereferences the freed `hu` struct. Furthermore, several data races and UAFs were identified in the teardown sequence: 1. Calling hci_uart_flush() from hci_uart_close() without effectively disabling write_work causes a race condition where both can concurrently double-free hu->tx_skb. This happens because protocol timers can concurrently invoke hci_uart_tx_wakeup() and requeue write_work. 2. Calling hci_free_dev(hdev) before hu->proto->close(hu) causes a UAF when vendor specific protocol close callbacks dereference hu->hdev. 3. In the initialization error paths, failing to take the proto_lock write lock before clearing PROTO_READY leads to races with active readers. Additionally, hci_uart_tty_receive() accesses hu->hdev outside the read lock, leading to UAFs if the initialization error path frees hdev concurrently. Fix these synchronization and lifecycle issues by: 1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first, followed immediately by a cancel_work_sync(&hu->write_work). Clearing the flag locks out concurrent protocol timers from successfully invoking hci_uart_tx_wakeup(), effectively rendering the cancellation permanent and preventing the tx_skb double-free. 2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip hu->proto->flush(). This is perfectly safe in the tty_close path because hu->proto->close() executes shortly after, which intrinsically purges all protocol SKB queues and tears down the state. 3. Relocating hu->proto->close(hu) strictly prior to hci_free_dev(hdev) across all close and error paths to prevent vendor-level UAFs. 4. Moving the hdev->stat.byte_rx increment in hci_uart_tty_receive() inside the proto_lock read-side critical section to safely synchronize with device unregistration. 5. Adding cancel_work_sync(&hu->write_work) to hci_uart_close() to safely flush the workqueue before hci_uart_flush() is invoked via the HCI core. 6. Utilizing cancel_work_sync() instead of disable_work_sync() across all paths to prevent permanently breaking user-space retry capabilities.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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，该漏洞源于蓝牙hci_uart的关闭和初始化路径中存在释放后重用和竞争条件，可能导致空指针取消引用。
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 3b799254cf6f481460719023d7a18f46651e5e7f ~ 78aad93e938f013d9272fe0ee168f27883afa95c -
Linux Linux 5.10 -

II. Public POCs for CVE-2026-46275

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III. Intelligence Information for CVE-2026-46275

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Patches & Fixes for CVE-2026-46275 (7)

Same Patch Batch · Linux · 2026-06-08 · 41 CVEs total

CVE-2026-46289 9.8 CRITICAL lib/scatterlist: fix length calculations in extract_kvec_to_sg
CVE-2026-46288 8.4 HIGH of: unittest: fix use-after-free in of_unittest_changeset()
CVE-2026-46307 8.3 HIGH wifi: ath5k: do not access array OOB
CVE-2026-46303 8.2 HIGH isofs: validate Rock Ridge CE continuation extent against volume size
CVE-2026-46274 7.8 HIGH io-wq: check that the predecessor is hashed in io_wq_remove_pending()
CVE-2026-46311 7.8 HIGH drm/amdgpu/userq: fix access to stale wptr mapping
CVE-2026-46280 7.8 HIGH lib: test_hmm: evict device pages on file close to avoid use-after-free
CVE-2026-46277 7.8 HIGH mm/zone_device: do not touch device folio after calling ->folio_free()
CVE-2026-46306 7.5 HIGH flow_dissector: do not dissect PPPoE PFC frames
CVE-2026-46304 7.5 HIGH nvmet: avoid recursive nvmet-wq flush in nvmet_ctrl_free
CVE-2026-46299 7.0 HIGH hfsplus: fix held lock freed on hfsplus_fill_super()
CVE-2026-46296 spi: s3c64xx: fix NULL-deref on driver unbind
CVE-2026-46298 pseries/papr-hvpipe: Fix race with interrupt handler
CVE-2026-46301 spi: topcliff-pch: fix use-after-free on unbind
CVE-2026-46302 selinux: allow multiple opens of /sys/fs/selinux/policy
CVE-2026-46314 drm/v3d: Reject empty multisync extension to prevent infinite loop
CVE-2025-71315 drm/vkms: Convert to DRM's vblank timer
CVE-2026-46305 staging: rtl8723bs: os_dep: avoid NULL pointer dereference in rtw_cbuf_alloc
CVE-2026-46313 media: intel/ipu6: fix error pointer dereference
CVE-2026-46308 pmdomain: mediatek: fix use-after-free in scpsys_get_bus_protection_legacy()

Showing top 20 of 41 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-46275

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