---
id: CVE-2025-40082
title: 'hfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()'
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  hfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()


  BUG: KASAN: slab-out-of-bounds in hfsplus_uni2asc+0xa71/0xb90
  fs/hfsplus/unicode.c:186

  Read of size 2 at addr…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ccf0ad56a779e6704c0b27f555dec847f50c7557 <
    343fe375a8dd6ee51a193a1c233b999f5ea4d479
  - >-
    Linux >= 13604b1d7e7b125fb428cddbec6b8d92baad25d5 <
    782acde47e127c98a113726e2ff8024bd65c0454
  - >-
    Linux >= 291bb5d931c6f3cd7227b913302a17be21cf53b0 <
    c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e
  - >-
    Linux >= f7534cbfac0a9ffa4fa17cacc6e8b6446dae24ee <
    5b5228964619b180f366940505b77255b1a03929
  - >-
    Linux >= 94458781aee6045bd3d0ad4b80b02886b9e2219b <
    857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e
  - >-
    Linux >= 94458781aee6045bd3d0ad4b80b02886b9e2219b <
    bea3e1d4467bcf292c8e54f080353d556d355e26
  - Linux 73f7da507d787b489761a0fa280716f84fa32b2f
  - Linux 76a4c6636a69d69409aa253b049b1be717a539c5
  - Linux 6f93694bcbc2c2ab3e01cd8fba2f296faf34e6b9
  - Linux 1ca69007e52a73bd8b84b988b61b319816ca8b01
  - Linux >= 5.15.190 < 5.15.200
  - Linux >= 6.1.149 < 6.1.163
  - Linux >= 6.6.103 < 6.6.124
  - Linux >= 6.12.43 < 6.12.70
  - Linux >= 5.4.297 < 5.5
  - Linux >= 5.10.241 < 5.11
  - Linux >= 6.15.11 < 6.16
  - Linux >= 6.16.2 < 6.17
  - Linux 6.17
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-15T21:56:46.761364Z'
published: '2025-10-28'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:02:37.613Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-40082'
references:
  - url: 'https://git.kernel.org/stable/c/343fe375a8dd6ee51a193a1c233b999f5ea4d479'
  - url: 'https://git.kernel.org/stable/c/782acde47e127c98a113726e2ff8024bd65c0454'
  - url: 'https://git.kernel.org/stable/c/c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e'
  - url: 'https://git.kernel.org/stable/c/5b5228964619b180f366940505b77255b1a03929'
  - url: 'https://git.kernel.org/stable/c/857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e'
  - url: 'https://git.kernel.org/stable/c/bea3e1d4467bcf292c8e54f080353d556d355e26'
tags:
  - cve.org
epss: 0.00192
epssPercentile: 0.0878
ingestedAt: '2026-10-15T22:48:25.546Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

hfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()

BUG: KASAN: slab-out-of-bounds in hfsplus_uni2asc+0xa71/0xb90 fs/hfsplus/unicode.c:186
Read of size 2 at addr ffff8880289ef218 by task syz.6.248/14290

CPU: 0 UID: 0 PID: 14290 Comm: syz.6.248 Not tainted 6.16.4 #1 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x5f0 mm/kasan/report.c:482
 kasan_report+0xca/0x100 mm/kasan/report.c:595
 hfsplus_uni2asc+0xa71/0xb90 fs/hfsplus/unicode.c:186
 hfsplus_listxattr+0x5b6/0xbd0 fs/hfsplus/xattr.c:738
 vfs_listxattr+0xbe/0x140 fs/xattr.c:493
 listxattr+0xee/0x190 fs/xattr.c:924
 filename_listxattr fs/xattr.c:958 [inline]
 path_listxattrat+0x143/0x360 fs/xattr.c:988
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcb/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe0e9fae16d
Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe0eae67f98 EFLAGS: 00000246 ORIG_RAX: 00000000000000c3
RAX: ffffffffffffffda RBX: 00007fe0ea205fa0 RCX: 00007fe0e9fae16d
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007fe0ea0480f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe0ea206038 R14: 00007fe0ea205fa0 R15: 00007fe0eae48000
 </TASK>

Allocated by task 14290:
 kasan_save_stack+0x24/0x50 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4333 [inline]
 __kmalloc_noprof+0x219/0x540 mm/slub.c:4345
 kmalloc_noprof include/linux/slab.h:909 [inline]
 hfsplus_find_init+0x95/0x1f0 fs/hfsplus/bfind.c:21
 hfsplus_listxattr+0x331/0xbd0 fs/hfsplus/xattr.c:697
 vfs_listxattr+0xbe/0x140 fs/xattr.c:493
 listxattr+0xee/0x190 fs/xattr.c:924
 filename_listxattr fs/xattr.c:958 [inline]
 path_listxattrat+0x143/0x360 fs/xattr.c:988
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcb/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

When hfsplus_uni2asc is called from hfsplus_listxattr,
it actually passes in a struct hfsplus_attr_unistr*.
The size of the corresponding structure is different from that of hfsplus_unistr,
so the previous fix (94458781aee6) is insufficient.
The pointer on the unicode buffer is still going beyond the allocated memory.

This patch introduces two warpper functions hfsplus_uni2asc_xattr_str and
hfsplus_uni2asc_str to process two unicode buffers,
struct hfsplus_attr_unistr* and struct hfsplus_unistr* respectively.
When ustrlen value is bigger than the allocated memory size,
the ustrlen value is limited to an safe size.

## Affected

- `Linux >= ccf0ad56a779e6704c0b27f555dec847f50c7557 < 343fe375a8dd6ee51a193a1c233b999f5ea4d479`
- `Linux >= 13604b1d7e7b125fb428cddbec6b8d92baad25d5 < 782acde47e127c98a113726e2ff8024bd65c0454`
- `Linux >= 291bb5d931c6f3cd7227b913302a17be21cf53b0 < c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e`
- `Linux >= f7534cbfac0a9ffa4fa17cacc6e8b6446dae24ee < 5b5228964619b180f366940505b77255b1a03929`
- `Linux >= 94458781aee6045bd3d0ad4b80b02886b9e2219b < 857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e`
- `Linux >= 94458781aee6045bd3d0ad4b80b02886b9e2219b < bea3e1d4467bcf292c8e54f080353d556d355e26`
- `Linux 73f7da507d787b489761a0fa280716f84fa32b2f`
- `Linux 76a4c6636a69d69409aa253b049b1be717a539c5`
- `Linux 6f93694bcbc2c2ab3e01cd8fba2f296faf34e6b9`
- `Linux 1ca69007e52a73bd8b84b988b61b319816ca8b01`
- `Linux >= 5.15.190 < 5.15.200`
- `Linux >= 6.1.149 < 6.1.163`
- `Linux >= 6.6.103 < 6.6.124`
- `Linux >= 6.12.43 < 6.12.70`
- `Linux >= 5.4.297 < 5.5`
- `Linux >= 5.10.241 < 5.11`
- `Linux >= 6.15.11 < 6.16`
- `Linux >= 6.16.2 < 6.17`
- `Linux 6.17`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.