{"id":"AZL-72923","summary":"CVE-2025-38443 affecting package kernel for versions less than 5.15.200.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: fix uaf in nbd_genl_connect() error path\n\nThere is a use-after-free issue in nbd:\n\nblock nbd6: Receive control failed (result -104)\nblock nbd6: shutting down sockets\n==================================================================\nBUG: KASAN: slab-use-after-free in recv_work+0x694/0xa80 drivers/block/nbd.c:1022\nWrite of size 4 at addr ffff8880295de478 by task kworker/u33:0/67\n\nCPU: 2 UID: 0 PID: 67 Comm: kworker/u33:0 Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 PREEMPT(full)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\nWorkqueue: nbd6-recv recv_work\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:408 [inline]\n print_report+0xc3/0x670 mm/kasan/report.c:521\n kasan_report+0xe0/0x110 mm/kasan/report.c:634\n check_region_inline mm/kasan/generic.c:183 [inline]\n kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189\n instrument_atomic_read_write include/linux/instrumented.h:96 [inline]\n atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]\n recv_work+0x694/0xa80 drivers/block/nbd.c:1022\n process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238\n process_scheduled_works kernel/workqueue.c:3319 [inline]\n worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400\n kthread+0x3c2/0x780 kernel/kthread.c:464\n ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \u003c/TASK\u003e\n\nnbd_genl_connect() does not properly stop the device on certain\nerror paths after nbd_start_device() has been called. This causes\nthe error path to put nbd-\u003econfig while recv_work continue to use\nthe config after putting it, leading to use-after-free in recv_work.\n\nThis patch moves nbd_start_device() after the backend file creation.","modified":"2026-04-01T05:22:14.341451Z","published":"2025-07-25T16:15:29Z","upstream":["CVE-2025-38443"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38443"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:2","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.200.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-72923.json"}}],"schema_version":"1.7.5"}