{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38593", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.028Z", "datePublished": "2025-08-19T17:03:18.960Z", "dateUpdated": "2026-08-05T12:03:15.011Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:03:15.011Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix double free in 'hci_discovery_filter_clear()'\n\nFunction 'hci_discovery_filter_clear()' frees 'uuids' array and then\nsets it to NULL. There is a tiny chance of the following race:\n\n'hci_cmd_sync_work()'\n\n 'update_passive_scan_sync()'\n\n 'hci_update_passive_scan_sync()'\n\n 'hci_discovery_filter_clear()'\n kfree(uuids);\n\n <-------------------------preempted-------------------------------->\n 'start_service_discovery()'\n\n 'hci_discovery_filter_clear()'\n kfree(uuids); // DOUBLE FREE\n\n <-------------------------preempted-------------------------------->\n\n uuids = NULL;\n\nTo fix it let's add locking around 'kfree()' call and NULL pointer\nassignment. Otherwise the following backtrace fires:\n\n[ ] ------------[ cut here ]------------\n[ ] kernel BUG at mm/slub.c:547!\n[ ] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP\n[ ] CPU: 3 UID: 0 PID: 246 Comm: bluetoothd Tainted: G O 6.12.19-kernel #1\n[ ] Tainted: [O]=OOT_MODULE\n[ ] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n[ ] pc : __slab_free+0xf8/0x348\n[ ] lr : __slab_free+0x48/0x348\n...\n[ ] Call trace:\n[ ] __slab_free+0xf8/0x348\n[ ] kfree+0x164/0x27c\n[ ] start_service_discovery+0x1d0/0x2c0\n[ ] hci_sock_sendmsg+0x518/0x924\n[ ] __sock_sendmsg+0x54/0x60\n[ ] sock_write_iter+0x98/0xf8\n[ ] do_iter_readv_writev+0xe4/0x1c8\n[ ] vfs_writev+0x128/0x2b0\n[ ] do_writev+0xfc/0x118\n[ ] __arm64_sys_writev+0x20/0x2c\n[ ] invoke_syscall+0x68/0xf0\n[ ] el0_svc_common.constprop.0+0x40/0xe0\n[ ] do_el0_svc+0x1c/0x28\n[ ] el0_svc+0x30/0xd0\n[ ] el0t_64_sync_handler+0x100/0x12c\n[ ] el0t_64_sync+0x194/0x198\n[ ] Code: 8b0002e6 eb17031f 54fffbe1 d503201f (d4210000)\n[ ] ---[ end trace 0000000000000000 ]---" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation requires issuing MGMT_OP_START_SERVICE_DISCOVERY/START_DISCOVERY on a local AF_BLUETOOTH HCI control socket via sendmsg/writev, so the attacker must have local system access. A remote/adjacent Bluetooth peer can only pump the workqueue side of the race (via LE connect/disconnect events), not the mgmt side, so local access is mandatory.\nAC:L - The attacker drives both sides of the race from the same socket — one thread loops START_SERVICE_DISCOVERY/STOP_DISCOVERY while another loops SET_SCAN_PARAMS/SET_DEVICE_FLAGS/adv-monitor ops to queue update_passive_scan_sync() — and the free paths take disjoint locks (hci_dev_lock vs hci_req_sync_lock), so the window is reachable and retryable indefinitely on a PREEMPT SMP kernel. The crash was in fact observed spontaneously in production with ordinary bluetoothd traffic.\nPR:L - The mgmt channel requires CAP_NET_ADMIN, but in the realistic Bluetooth deployments (Android's non-root AID_BLUETOOTH service, ChromeOS/embedded/automotive BT daemons) that capability is held by an unprivileged, SELinux-confined, remotely-reachable service process rather than by root, so a compromised Bluetooth daemon — far short of full admin — suffices to reach the bug.\nUI:N - No victim action is needed; the attacker's own threads issue every mgmt command required to open and hit the race window. No pairing, mount, or user-initiated scan is involved.\nS:U - The double free corrupts kernel heap metadata within the same kernel security authority; there is no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The double free of an attacker-sized (up to ~64 KB) and attacker-filled buffer corrupts the SLUB freelist and leaves a dangling hdev->discovery.uuids that is still dereferenced by is_filter_match()/eir_has_uuids() on the advertisement RX path, yielding a use-after-free read that can be groomed into arbitrary kernel memory disclosure.\nI:H - A double free hands the same slab object to two owners, a classic primitive for cross-cache/overlapping-allocation attacks that convert into arbitrary kernel writes and control-flow hijack; the attacker fully controls the object's size class and contents, making the grooming practical.\nA:H - The reported, directly observed consequence is a kernel BUG() in __slab_free (mm/slub.c:547) taking down the machine, and freelist corruption reliably panics the kernel even when not weaponized further." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/bluetooth/hci_core.h" ], "versions": [ { "version": "ad383c2c65a5baf16e334cd40a013cc302176891", "lessThan": "86f3dcd1f331cfd4fd7ec88906955134ec51afbe", "status": "affected", "versionType": "git" }, { "version": "ad383c2c65a5baf16e334cd40a013cc302176891", "lessThan": "7ce9bb0b95fc280e9212b8922590c492ca1d9c39", "status": "affected", "versionType": "git" }, { "version": "ad383c2c65a5baf16e334cd40a013cc302176891", "lessThan": "16852eccbdfaf41a666705e3f8be55cf2864c5ca", "status": "affected", "versionType": "git" }, { "version": "ad383c2c65a5baf16e334cd40a013cc302176891", "lessThan": "a351ff6b8ecca4229afaa0d98042bead8de64799", "status": "affected", "versionType": "git" }, { "version": "ad383c2c65a5baf16e334cd40a013cc302176891", "lessThan": "f8069f34c4c976786ded97498012225af87435d7", "status": "affected", "versionType": "git" }, { "version": "ad383c2c65a5baf16e334cd40a013cc302176891", "lessThan": "2935e556850e9c94d7a00adf14d3cd7fe406ac03", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/bluetooth/hci_core.h" ], "versions": [ { "version": "5.17", "status": "affected" }, { "version": "0", "lessThan": "5.17", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.159", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.117", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.42", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.10", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.1", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.1.159" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.6.117" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.12.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.15.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.16.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/86f3dcd1f331cfd4fd7ec88906955134ec51afbe" }, { "url": "https://git.kernel.org/stable/c/7ce9bb0b95fc280e9212b8922590c492ca1d9c39" }, { "url": "https://git.kernel.org/stable/c/16852eccbdfaf41a666705e3f8be55cf2864c5ca" }, { "url": "https://git.kernel.org/stable/c/a351ff6b8ecca4229afaa0d98042bead8de64799" }, { "url": "https://git.kernel.org/stable/c/f8069f34c4c976786ded97498012225af87435d7" }, { "url": "https://git.kernel.org/stable/c/2935e556850e9c94d7a00adf14d3cd7fe406ac03" } ], "title": "Bluetooth: hci_sync: fix double free in 'hci_discovery_filter_clear()'", "x_generator": { "engine": "bippy-1.2.0" } } } }