CVE-2025-38051

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> smb: client: Fix use-after-free in cifs_fill_dirent<br /> <br /> There is a race condition in the readdir concurrency process, which may<br /> access the rsp buffer after it has been released, triggering the<br /> following KASAN warning.<br /> <br /> ==================================================================<br /> BUG: KASAN: slab-use-after-free in cifs_fill_dirent+0xb03/0xb60 [cifs]<br /> Read of size 4 at addr ffff8880099b819c by task a.out/342975<br /> <br /> CPU: 2 UID: 0 PID: 342975 Comm: a.out Not tainted 6.15.0-rc6+ #240 PREEMPT(full)<br /> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014<br /> Call Trace:<br /> <br /> dump_stack_lvl+0x53/0x70<br /> print_report+0xce/0x640<br /> kasan_report+0xb8/0xf0<br /> cifs_fill_dirent+0xb03/0xb60 [cifs]<br /> cifs_readdir+0x12cb/0x3190 [cifs]<br /> iterate_dir+0x1a1/0x520<br /> __x64_sys_getdents+0x134/0x220<br /> do_syscall_64+0x4b/0x110<br /> entry_SYSCALL_64_after_hwframe+0x76/0x7e<br /> RIP: 0033:0x7f996f64b9f9<br /> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89<br /> f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 3d 01<br /> f0 ff ff 0d f7 c3 0c 00 f7 d8 64 89 8<br /> RSP: 002b:00007f996f53de78 EFLAGS: 00000207 ORIG_RAX: 000000000000004e<br /> RAX: ffffffffffffffda RBX: 00007f996f53ecdc RCX: 00007f996f64b9f9<br /> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003<br /> RBP: 00007f996f53dea0 R08: 0000000000000000 R09: 0000000000000000<br /> R10: 0000000000000000 R11: 0000000000000207 R12: ffffffffffffff88<br /> R13: 0000000000000000 R14: 00007ffc8cd9a500 R15: 00007f996f51e000<br /> <br /> <br /> Allocated by task 408:<br /> kasan_save_stack+0x20/0x40<br /> kasan_save_track+0x14/0x30<br /> __kasan_slab_alloc+0x6e/0x70<br /> kmem_cache_alloc_noprof+0x117/0x3d0<br /> mempool_alloc_noprof+0xf2/0x2c0<br /> cifs_buf_get+0x36/0x80 [cifs]<br /> allocate_buffers+0x1d2/0x330 [cifs]<br /> cifs_demultiplex_thread+0x22b/0x2690 [cifs]<br /> kthread+0x394/0x720<br /> ret_from_fork+0x34/0x70<br /> ret_from_fork_asm+0x1a/0x30<br /> <br /> Freed by task 342979:<br /> kasan_save_stack+0x20/0x40<br /> kasan_save_track+0x14/0x30<br /> kasan_save_free_info+0x3b/0x60<br /> __kasan_slab_free+0x37/0x50<br /> kmem_cache_free+0x2b8/0x500<br /> cifs_buf_release+0x3c/0x70 [cifs]<br /> cifs_readdir+0x1c97/0x3190 [cifs]<br /> iterate_dir+0x1a1/0x520<br /> __x64_sys_getdents64+0x134/0x220<br /> do_syscall_64+0x4b/0x110<br /> entry_SYSCALL_64_after_hwframe+0x76/0x7e<br /> <br /> The buggy address belongs to the object at ffff8880099b8000<br /> which belongs to the cache cifs_request of size 16588<br /> The buggy address is located 412 bytes inside of<br /> freed 16588-byte region [ffff8880099b8000, ffff8880099bc0cc)<br /> <br /> The buggy address belongs to the physical page:<br /> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x99b8<br /> head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0<br /> anon flags: 0x80000000000040(head|node=0|zone=1)<br /> page_type: f5(slab)<br /> raw: 0080000000000040 ffff888001e03400 0000000000000000 dead000000000001<br /> raw: 0000000000000000 0000000000010001 00000000f5000000 0000000000000000<br /> head: 0080000000000040 ffff888001e03400 0000000000000000 dead000000000001<br /> head: 0000000000000000 0000000000010001 00000000f5000000 0000000000000000<br /> head: 0080000000000003 ffffea0000266e01 00000000ffffffff 00000000ffffffff<br /> head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008<br /> page dumped because: kasan: bad access detected<br /> <br /> Memory state around the buggy address:<br /> ffff8880099b8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb<br /> ffff8880099b8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb<br /> &gt;ffff8880099b8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb<br /> ^<br /> ffff8880099b8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb<br /> ffff8880099b8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb<br /> ==================================================================<br /> <br /> POC is available in the link [1].<br /> <br /> The problem triggering process is as follows:<br /> <br /> Process 1 Process 2<br /> -----------------------------------<br /> ---truncated---