CVE-2025-21969 (GCVE-0-2025-21969)
Vulnerability from cvelistv5
Published
2025-04-01 15:47
Modified
2026-05-23 15:57
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: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd After the hci sync command releases l2cap_conn, the hci receive data work queue references the released l2cap_conn when sending to the upper layer. Add hci dev lock to the hci receive data work queue to synchronize the two. [1] BUG: KASAN: slab-use-after-free in l2cap_send_cmd+0x187/0x8d0 net/bluetooth/l2cap_core.c:954 Read of size 8 at addr ffff8880271a4000 by task kworker/u9:2/5837 CPU: 0 UID: 0 PID: 5837 Comm: kworker/u9:2 Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: hci1 hci_rx_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 l2cap_build_cmd net/bluetooth/l2cap_core.c:2964 [inline] l2cap_send_cmd+0x187/0x8d0 net/bluetooth/l2cap_core.c:954 l2cap_sig_send_rej net/bluetooth/l2cap_core.c:5502 [inline] l2cap_sig_channel net/bluetooth/l2cap_core.c:5538 [inline] l2cap_recv_frame+0x221f/0x10db0 net/bluetooth/l2cap_core.c:6817 hci_acldata_packet net/bluetooth/hci_core.c:3797 [inline] hci_rx_work+0x508/0xdb0 net/bluetooth/hci_core.c:4040 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Allocated by task 5837: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4329 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] l2cap_conn_add+0xa9/0x8e0 net/bluetooth/l2cap_core.c:6860 l2cap_connect_cfm+0x115/0x1090 net/bluetooth/l2cap_core.c:7239 hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline] hci_remote_features_evt+0x68e/0xac0 net/bluetooth/hci_event.c:3726 hci_event_func net/bluetooth/hci_event.c:7473 [inline] hci_event_packet+0xac2/0x1540 net/bluetooth/hci_event.c:7525 hci_rx_work+0x3f3/0xdb0 net/bluetooth/hci_core.c:4035 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Freed by task 54: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4613 [inline] kfree+0x196/0x430 mm/slub.c:4761 l2cap_connect_cfm+0xcc/0x1090 net/bluetooth/l2cap_core.c:7235 hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline] hci_conn_failed+0x287/0x400 net/bluetooth/hci_conn.c:1266 hci_abort_conn_sync+0x56c/0x11f0 net/bluetooth/hci_sync.c:5603 hci_cmd_sync_work+0x22b/0x400 net/bluetooth/hci_sync.c:332 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entr ---truncated---
References
Impacted products
Vendor Product Version
Linux Linux Version: 9b3628d79b46f06157affc56fdb218fdd4988321
Version: 9b3628d79b46f06157affc56fdb218fdd4988321
Version: 9b3628d79b46f06157affc56fdb218fdd4988321
Version: 9b3628d79b46f06157affc56fdb218fdd4988321
Version: 995c917d6818b39308ac6baf3f6573cb0486a238
Version: 5.17.14   ≤
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{
  "containers": {
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        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 7.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
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              "content": {
                "id": "CVE-2025-21969",
                "options": [
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                    "Automatable": "no"
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                "role": "CISA Coordinator",
                "timestamp": "2025-10-01T17:15:33.042789Z",
                "version": "2.0.3"
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        "problemTypes": [
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              {
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                "description": "CWE-416 Use After Free",
                "lang": "en",
                "type": "CWE"
              }
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        "providerMetadata": {
          "dateUpdated": "2025-10-01T17:15:36.237Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
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              "version": "6.13.8",
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              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd\n\nAfter the hci sync command releases l2cap_conn, the hci receive data work\nqueue references the released l2cap_conn when sending to the upper layer.\nAdd hci dev lock to the hci receive data work queue to synchronize the two.\n\n[1]\nBUG: KASAN: slab-use-after-free in l2cap_send_cmd+0x187/0x8d0 net/bluetooth/l2cap_core.c:954\nRead of size 8 at addr ffff8880271a4000 by task kworker/u9:2/5837\n\nCPU: 0 UID: 0 PID: 5837 Comm: kworker/u9:2 Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\nWorkqueue: hci1 hci_rx_work\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0x169/0x550 mm/kasan/report.c:489\n kasan_report+0x143/0x180 mm/kasan/report.c:602\n l2cap_build_cmd net/bluetooth/l2cap_core.c:2964 [inline]\n l2cap_send_cmd+0x187/0x8d0 net/bluetooth/l2cap_core.c:954\n l2cap_sig_send_rej net/bluetooth/l2cap_core.c:5502 [inline]\n l2cap_sig_channel net/bluetooth/l2cap_core.c:5538 [inline]\n l2cap_recv_frame+0x221f/0x10db0 net/bluetooth/l2cap_core.c:6817\n hci_acldata_packet net/bluetooth/hci_core.c:3797 [inline]\n hci_rx_work+0x508/0xdb0 net/bluetooth/hci_core.c:4040\n process_one_work kernel/workqueue.c:3229 [inline]\n process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310\n worker_thread+0x870/0xd30 kernel/workqueue.c:3391\n kthread+0x2f0/0x390 kernel/kthread.c:389\n ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n \u003c/TASK\u003e\n\nAllocated by task 5837:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n poison_kmalloc_redzone mm/kasan/common.c:377 [inline]\n __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394\n kasan_kmalloc include/linux/kasan.h:260 [inline]\n __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4329\n kmalloc_noprof include/linux/slab.h:901 [inline]\n kzalloc_noprof include/linux/slab.h:1037 [inline]\n l2cap_conn_add+0xa9/0x8e0 net/bluetooth/l2cap_core.c:6860\n l2cap_connect_cfm+0x115/0x1090 net/bluetooth/l2cap_core.c:7239\n hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline]\n hci_remote_features_evt+0x68e/0xac0 net/bluetooth/hci_event.c:3726\n hci_event_func net/bluetooth/hci_event.c:7473 [inline]\n hci_event_packet+0xac2/0x1540 net/bluetooth/hci_event.c:7525\n hci_rx_work+0x3f3/0xdb0 net/bluetooth/hci_core.c:4035\n process_one_work kernel/workqueue.c:3229 [inline]\n process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310\n worker_thread+0x870/0xd30 kernel/workqueue.c:3391\n kthread+0x2f0/0x390 kernel/kthread.c:389\n ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n\nFreed by task 54:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582\n poison_slab_object mm/kasan/common.c:247 [inline]\n __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264\n kasan_slab_free include/linux/kasan.h:233 [inline]\n slab_free_hook mm/slub.c:2353 [inline]\n slab_free mm/slub.c:4613 [inline]\n kfree+0x196/0x430 mm/slub.c:4761\n l2cap_connect_cfm+0xcc/0x1090 net/bluetooth/l2cap_core.c:7235\n hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline]\n hci_conn_failed+0x287/0x400 net/bluetooth/hci_conn.c:1266\n hci_abort_conn_sync+0x56c/0x11f0 net/bluetooth/hci_sync.c:5603\n hci_cmd_sync_work+0x22b/0x400 net/bluetooth/hci_sync.c:332\n process_one_work kernel/workqueue.c:3229 [inline]\n process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310\n worker_thread+0x870/0xd30 kernel/workqueue.c:3391\n kthread+0x2f0/0x390 kernel/kthread.c:389\n ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entr\n---truncated---"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-23T15:57:31.921Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c96cce853542b3b13da3738f35ef1be8cfcc9d1d"
        },
        {
          "url": "https://git.kernel.org/stable/c/f8094625a591eeb0b75b1bd9e713fac1d93f5ca9"
        },
        {
          "url": "https://git.kernel.org/stable/c/7790a79c6fce8d5d552bc64f5c82819f719e4f28"
        },
        {
          "url": "https://git.kernel.org/stable/c/b4f82f9ed43aefa79bec2504ae8c29be0c0f5d1d"
        }
      ],
      "title": "Bluetooth: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-21969",
    "datePublished": "2025-04-01T15:47:03.408Z",
    "dateReserved": "2024-12-29T08:45:45.796Z",
    "dateUpdated": "2026-05-23T15:57:31.921Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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