{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2023-53862",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2025-12-09T01:27:17.829Z",
"datePublished": "2025-12-09T01:30:30.902Z",
"dateUpdated": "2026-08-05T09:16:26.547Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-08-05T09:16:26.547Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfs: fix missing hfs_bnode_get() in __hfs_bnode_create\n\nSyzbot found a kernel BUG in hfs_bnode_put():\n\n kernel BUG at fs/hfs/bnode.c:466!\n invalid opcode: 0000 [#1] PREEMPT SMP KASAN\n CPU: 0 PID: 3634 Comm: kworker/u4:5 Not tainted 6.1.0-rc7-syzkaller-00190-g97ee9d1c1696 #0\n Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022\n Workqueue: writeback wb_workfn (flush-7:0)\n RIP: 0010:hfs_bnode_put+0x46f/0x480 fs/hfs/bnode.c:466\n 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\n RSP: 0018:ffffc90003b4f258 EFLAGS: 00010293\n RAX: ffffffff825e318f RBX: 0000000000000000 RCX: ffff8880739dd7c0\n RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n RBP: ffffc90003b4f430 R08: ffffffff825e2d9b R09: ffffed10045157d1\n R10: ffffed10045157d1 R11: 1ffff110045157d0 R12: ffff8880228abe80\n R13: ffff88807016c000 R14: dffffc0000000000 R15: ffff8880228abe00\n FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007fa6ebe88718 CR3: 000000001e93d000 CR4: 00000000003506f0\n DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n Call Trace:\n \n hfs_write_inode+0x1bc/0xb40\n write_inode fs/fs-writeback.c:1440 [inline]\n __writeback_single_inode+0x4d6/0x670 fs/fs-writeback.c:1652\n writeback_sb_inodes+0xb3b/0x18f0 fs/fs-writeback.c:1878\n __writeback_inodes_wb+0x125/0x420 fs/fs-writeback.c:1949\n wb_writeback+0x440/0x7b0 fs/fs-writeback.c:2054\n wb_check_start_all fs/fs-writeback.c:2176 [inline]\n wb_do_writeback fs/fs-writeback.c:2202 [inline]\n wb_workfn+0x827/0xef0 fs/fs-writeback.c:2235\n process_one_work+0x877/0xdb0 kernel/workqueue.c:2289\n worker_thread+0xb14/0x1330 kernel/workqueue.c:2436\n kthread+0x266/0x300 kernel/kthread.c:376\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306\n \n\nThe BUG_ON() is triggered at here:\n\n/* Dispose of resources used by a node */\nvoid hfs_bnode_put(struct hfs_bnode *node)\n{\n\tif (node) {\n \t\t\n \t\tBUG_ON(!atomic_read(&node->refcnt)); <- we have issue here!!!!\n \t\t\n \t}\n}\n\nBy tracing the refcnt, I found the node is created by hfs_bmap_alloc()\nwith refcnt 1. Then the node is used by hfs_btree_write(). There is a\nmissing of hfs_bnode_get() after find the node. The issue happened in\nfollowing path:\n\n\n hfs_bmap_alloc\n hfs_bnode_find\n __hfs_bnode_create <- allocate a new node with refcnt 1.\n hfs_bnode_put <- decrease the refcnt\n\n\n hfs_btree_write\n hfs_bnode_find\n __hfs_bnode_create\n hfs_bnode_findhash <- find the node without refcnt increased.\n hfs_bnode_put\t <- trigger the BUG_ON() since refcnt is 0."
}
],
"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 - HFS is a local disk/removable-media filesystem; the race is driven entirely through local syscalls (`sync()`, `link()`, `create()`) against a mounted HFS volume. No network protocol handling is involved.\nAC:L - The attacker controls both sides of the race — one thread loops `sync()`/`fsync()` to drive `hfs_write_inode()` → `hfs_btree_write()` while another loops directory creations to drive `hfs_bmap_alloc()`, both landing in `hfs_bnode_find(tree, 0)`. The window can be retried indefinitely at will.\nPR:L - Once an HFS volume is mounted (udisks2 auto-mount of removable Apple media, kiosk/desktop, or an admin-mounted share), any unprivileged local user with write access to it can issue the concurrent syscalls that trigger the missing reference. No capability is needed to reach the racing paths.\nUI:N - With the HFS volume already mounted — the normal state on systems that auto-mount removable media — no victim action is required; the attacker triggers the race purely with their own concurrent syscalls.\nS:U - The corruption is confined to kernel memory managed by the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The borrowed reference lets refcnt reach zero while another thread still holds the node, so `hfs_bnode_free()` kfree's the `struct hfs_bnode` and drops the btree page references underneath a live user — a use-after-free that permits reading reclaimed kernel heap contents.\nI:H - The same premature free gives a write-after-free on the reallocated `hfs_bnode` slab object and on the released btree pages, which can be heap-sprayed to corrupt adjacent kernel objects and hijack control flow.\nA:H - Syzbot demonstrated a hard `BUG_ON(!atomic_read(&node->refcnt))` at fs/hfs/bnode.c:466 inside the writeback kworker, killing the flusher thread and oopsing (panic with panic_on_oops); the UAF path additionally causes memory corruption crashes."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/hfs/bnode.c"
],
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"status": "affected",
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{
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"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
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],
"versions": [
{
"version": "2.6.12",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.12",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "4.14.308",
"lessThanOrEqual": "4.14.*",
"status": "unaffected",
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},
{
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"lessThanOrEqual": "4.19.*",
"status": "unaffected",
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},
{
"version": "5.4.235",
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.10.173",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.15.99",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.1.16",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.2.3",
"lessThanOrEqual": "6.2.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.3",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.12",
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},
{
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"references": [
{
"url": "https://git.kernel.org/stable/c/062af3e9930762d1fd22946748d34e0d859e4a8e"
},
{
"url": "https://git.kernel.org/stable/c/3a9065a33988c02789722be612f7c42fb8ebbb22"
},
{
"url": "https://git.kernel.org/stable/c/eda6879272e4df5456afc36642052ea066f58410"
},
{
"url": "https://git.kernel.org/stable/c/dc9f78b6d254427a06e568f2887b1011ef3143ef"
},
{
"url": "https://git.kernel.org/stable/c/2cab8db14566cf6a516c1f103a60cf6b7f54b1e5"
},
{
"url": "https://git.kernel.org/stable/c/8140cdc57bc5844cd5e1392673ec2dbf8fdc6940"
},
{
"url": "https://git.kernel.org/stable/c/38d72e6604b9f96dffcc0565090cc01622a37b2a"
},
{
"url": "https://git.kernel.org/stable/c/a9dc087fd3c484fd1ed18c5efb290efaaf44ce03"
}
],
"title": "hfs: fix missing hfs_bnode_get() in __hfs_bnode_create",
"x_generator": {
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}