CVE-2026-31772

HIGH EPSS 3.9%
Published May 1, 20262mo ago · Modified Jun 17, 20262w ago
7.8 CVSS 3.1
High
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Published May 1, 2026 2mo ago
Last Modified Jun 17, 2026 2w ago

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync hci_le_big_create_sync() uses DEFINE_FLEX to allocate a struct hci_cp_le_big_create_sync on the stack with room for 0x11 (17) BIS entries. However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31) entries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller hci_conn_big_create_sync(). When conn->num_bis is between 18 and 31, the memcpy that copies conn->bis into cp->bis writes up to 14 bytes past the stack buffer, corrupting adjacent stack memory. This is trivially reproducible: binding an ISO socket with bc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will eventually trigger hci_le_big_create_sync() from the HCI command sync worker, causing a KASAN-detectable stack-out-of-bounds write: BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0 Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71 Fix this by changing the DEFINE_FLEX count from the incorrect 0x11 to HCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that conn->bis can actually carry.

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
3.9% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-787 Out-of-bounds Write Memory Safety

Affected Products 11

VendorProductVersionRange
linuxlinux_kernel*≥6.11.11  –  <6.12
linuxlinux_kernel*≥6.12.2  –  <6.12.81
linuxlinux_kernel*≥6.13.1  –  <6.18.22
linuxlinux_kernel*≥6.19  –  <6.19.12
linuxlinux_kernel6.13any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any

References 4

  • git.kernel.org https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9
    Patch