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CVE-2026-90256— Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind

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.

在 Linux 内核中，已修复以下漏洞： 蓝牙：L2CAP：使用 proto_lock 保护 l2cap_data，以修复 l2cap_disconn_ind 中的竞态条件 在 的访问路径中，通过 访问时未加锁保护。如果 被并发删除，就会发生 使用已释放的指针（Use-After-Free, UAF）。 由于 在 中是被同步禁用的，因此无法在 中获取 。 修复方案：使用 来保护对 的访问，同时其他访问路径仍持有 进行保护。

AI Predicted 5.5 Difficulty: Hard

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux ab4eedb790cae44313759b50fe47da285e2519d5< b495a3a9b33bc4e4613e685bf5c96c136caa22d8 affected
ab4eedb790cae44313759b50fe47da285e2519d5< 2b66c83ff1751d6bd3201b3017206262ab46dc05 affected
efc30877bd4bc85fefe98d80af60fafc86e5775e affected
f87271d21dd4ee83857ca11b94e7b4952749bbae affected
18ab6b6078fa8191ca30a3065d57bf35d5635761 affected
6.6.84< 6.7 affected
6.12.20< 6.13 affected
6.13.8< 6.14 affected
… +4 more rows
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I. Basic Information for CVE-2026-90256

Vulnerability Information
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Vulnerability Title
Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind hci_conn::l2cap_data is accessed without locks in l2cap_disconn_ind via hci_conn_timeout (disc_work) -> hci_proto_disconn_ind -> l2cap_disconn_ind. This is UAF if the l2cap_conn is deleted concurrently. disc_work is disabled sync in hci_conn_del(), so we cannot take hci_dev_lock in disc_work. Fix by using proto_lock to guard l2cap_data, in addition to hdev->lock which is held in other access paths.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux ab4eedb790cae44313759b50fe47da285e2519d5 ~ b495a3a9b33bc4e4613e685bf5c96c136caa22d8 -
Linux Linux 6.14 -

II. Public POCs for CVE-2026-90256

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III. Intelligence Information for CVE-2026-90256

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Patches & Fixes for CVE-2026-90256 (1)

Other References for CVE-2026-90256 (1)

Same Patch Batch · Linux · 2026-09-17 · 602 CVEs total

CVE-2026-90257 Bluetooth: virtio_bt: avoid OOB read of build info string
CVE-2026-90238 media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
CVE-2026-90240 iommu/vt-d: Flush context cache with correct SID when tearing down aliases
CVE-2026-90239 media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
CVE-2026-90241 iommu/vt-d: Tear down scalable-mode context on probe failure
CVE-2026-90243 iommu/vt-d: Clear Present bit before tearing down copied context entry
CVE-2026-90242 iommu/vt-d: Fix iopf_refcount leak on RID domain replacement
CVE-2026-90244 iommu/dma: Restore locking around msi_page_list
CVE-2026-90245 fbdev: kyro: Validate overlay viewport coordinates
CVE-2026-90246 apparmor: fix integer overflow in verify_tags() bounds check
CVE-2026-90247 bpf: Fix mmap_lock leak in irq_work path
CVE-2026-90248 net/sched: cls_api: fix teardown of an adopted proto on insert-race loss
CVE-2026-90249 iio: light: gp2ap002: Fix unbalanced runtime PM on repeated event writes
CVE-2026-90250 bpf, cgroup: Fix storage null-ptr-deref after replacing prog
CVE-2026-90251 Bluetooth: MSFT: validate evt_prefix_len against the response length
CVE-2026-90253 Bluetooth: MGMT: free the mesh send cancel command when it is cancelled
CVE-2026-90252 Bluetooth: MGMT: free the HCI command when it is cancelled
CVE-2026-90254 Bluetooth: hci_sync: free the advertising instance on the failure and cancel paths
CVE-2026-90255 Bluetooth: hci_conn: fix the SCO setup context lifetime
CVE-2026-90267 scsi: sd: Fix special_vec mempool leak when scsi_alloc_sgtables() fails

Showing top 20 of 602 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-90256

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