CVE-2026-31772 (GCVE-0-2026-31772)
Vulnerability from cvelistv5
Published
2026-05-01 14:15
Modified
2026-10-19 19:06
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 91d19383b7ed035e22165ae5c836e50bb9f95fbe
Version: 42ecf1947135110ea08abeaca39741636f9a2285
Version: 42ecf1947135110ea08abeaca39741636f9a2285
Version: 42ecf1947135110ea08abeaca39741636f9a2285
Version: 8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd
Version: 6.12.2   ≤
Version: 6.11.11   ≤
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