# CVE-2023-53862: linux: In the Linux kernel, the following vulnerability has been resolved:  hfs: fix missing hfs_bnode_get() in __hfs_bnode_...

CVE-2023-53862 is fixed in linux on 1 platform, first by DEBIAN-CVE-2023-53862, released December 9, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2023-53862
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 9, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  hfs: fix missing hfs_bnode_get() in __hfs_bnode_create  Syzbot found a kernel BUG in hfs_bnode_put():   kernel BUG at fs/hfs/bnode.c:466!  invalid opcode: 0000 [#1] PREEMPT SMP KASAN  CPU: 0 PID: 3634 Comm: kworker/u4:5 Not tainted 6.1.0-rc7-syzkaller-00190-g97ee9d1c1696 #0  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022  Workqueue: writeback wb_workfn (flush-7:0)  RIP: 0010:hfs_bnode_put+0x46f/0x480 fs/hfs/bnode.c:466  Code: 8a 80 ff e9 73 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c a0 fe ff ff 48 89 df e8 db 8a 80 ff e9 93 fe ff ff e8 a1 68 2c ff <0f> 0b e8 9a 68 2c ff 0f 0b 0f 1f 84 00 00 00 00 00 55 41 57 41 56  RSP: 0018:ffffc90003b4f258 EFLAGS: 00010293  RAX: ffffffff825e318f RBX: 0000000000000000 RCX: ffff8880739dd7c0  RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000  RBP: ffffc90003b4f430 R08: ffffffff825e2d9b R09: ffffed10045157d1  R10: ffffed10045157d1 R11: 1ffff110045157d0 R12: ffff8880228abe80  R13: ffff88807016c000 R14: dffffc0000000000 R15: ffff8880228abe00  FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033  CR2: 00007fa6ebe88718 CR3: 000000001e93d000 CR4: 00000000003506f0  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400  Call Trace:   <TASK>   hfs_write_inode+0x1bc/0xb40   write_inode fs/fs-writeback.c:1440 [inline]   __writeback_single_inode+0x4d6/0x670 fs/fs-writeback.c:1652   writeback_sb_inodes+0xb3b/0x18f0 fs/fs-writeback.c:1878   __writeback_inodes_wb+0x125/0x420 fs/fs-writeback.c:1949   wb_writeback+0x440/0x7b0 fs/fs-writeback.c:2054   wb_check_start_all fs/fs-writeback.c:2176 [inline]   wb_do_writeback fs/fs-writeback.c:2202 [inline]   wb_workfn+0x827/0xef0 fs/fs-writeback.c:2235   process_one_work+0x877/0xdb0 kernel/workqueue.c:2289   worker_thread+0xb14/0x1330 kernel/workqueue.c:2436   kthread+0x266/0x300 kernel/kthread.c:376   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306   </TASK>  The BUG_ON() is triggered at here:  /* Dispose of resources used by a node */ void hfs_bnode_put(struct hfs_bnode *node) { 	if (node) {  		<skipped>  		BUG_ON(!atomic_read(&node->refcnt)); <- we have issue here!!!!  		<skipped>  	} }  By tracing the refcnt, I found the node is created by hfs_bmap_alloc() with refcnt 1.  Then the node is used by hfs_btree_write().  There is a missing of hfs_bnode_get() after find the node.  The issue happened in following path:  <alloc>  hfs_bmap_alloc    hfs_bnode_find      __hfs_bnode_create   <- allocate a new node with refcnt 1.    hfs_bnode_put          <- decrease the refcnt  <write>  hfs_btree_write    hfs_bnode_find      __hfs_bnode_create        hfs_bnode_findhash <- find the node without refcnt increased.    hfs_bnode_put	  <- trigger the BUG_ON() since refcnt is 0.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.20-1 | [DEBIAN-CVE-2023-53862](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53862.md) | Dec 9, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.1.20-1 | [DEBIAN-CVE-2023-53862](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53862.md) | Dec 9, 2025 |
| Linux | linux Debian 14 | 6.1.20-1 | [DEBIAN-CVE-2023-53862](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53862.md) | Dec 9, 2025 |

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