{"id":"CVE-2026-31772","revision":null,"records":[{"revision":"3a29726828d541e8a22ade3ef3c65c0b","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-31772","aliases":[],"title":"Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync\n\nhci_le_big_create_sync() uses DEFINE_FLEX to allocate a\nstruct hci_cp_le_big_create_sync on the stack with room for 0x11 (17)\nBIS entries. However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31)\nentries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller\nhci_conn_big_create_sync(). When conn->num_bis is between 18 and 31,\nthe memcpy that copies conn->bis into cp->bis writes up to 14 bytes\npast the stack buffer, corrupting adjacent stack memory.\n\nThis is trivially reproducible: binding an ISO socket with\nbc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will\neventually trigger hci_le_big_create_sync() from the HCI command\nsync worker, causing a KASAN-detectable stack-out-of-bounds write:\n\n BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0\n Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71\n\nFix this by changing the DEFINE_FLEX count from the incorrect 0x11 to\nHCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that\nconn->bis can actually carry.","state":0,"publishedAt":"2026-05-01T14:15:00.582+00:00","modifiedAt":"2026-10-19T19:06:08.134+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/bluetooth/hci_sync.c\"\n ],\n \"versions\": [\n {\n \"version\": \"91d19383b7ed035e22165ae5c836e50bb9f95fbe\",\n \"lessThan\": \"f5d446624345d309e7a4a1b27ea9f028d6a8c5d9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"42ecf1947135110ea08abeaca39741636f9a2285\",\n \"lessThan\": \"aba0aea354015794e8312dd7efe726967e58aefe\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"42ecf1947135110ea08abeaca39741636f9a2285\",\n \"lessThan\": \"eaf32002ca7b1ba51c9f140991fd9febe6de79f0\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"42ecf1947135110ea08abeaca39741636f9a2285\",\n \"lessThan\": \"bc39a094730ce062fa034a529c93147c096cb488\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"6.12.2\",\n \"lessThan\": \"6.12.81\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.11.11\",\n \"lessThan\": \"6.12\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/bluetooth/hci_sync.c\"\n ],\n \"versions\": [\n {\n \"version\": \"6.13\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"6.13\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.81\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.22\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.19.12\",\n \"lessThanOrEqual\": \"6.19.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.0\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9","https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe","https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0","https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31772","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-31772","identifiers":["CVE-2026-31772"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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