Linux: Out-of-bounds Read
CVE-2025-40082 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 343fe375a8dd6ee51a193a1c233b999f5ea4d479, 782acde47e127c98a113726e2ff8024bd65c0454, c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.19% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 343fe375a8dd6ee51a193a1c233b999f5ea4d479 or 782acde47e127c98a113726e2ff8024bd65c0454 or c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e or 5b5228964619b180f366940505b77255b1a03929, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.5 or 5.11 or 5.15.200 or 6.1.163, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | ccf0ad56a779e6704c0b27f555dec847f50c7557 up to, but not including, 343fe375a8dd6ee51a193a1c233b999f5ea4d479; 13604b1d7e7b125fb428cddbec6b8d92baad25d5 up to, but not including, 782acde47e127c98a113726e2ff8024bd65c0454; 291bb5d931c6f3cd7227b913302a17be21cf53b0 up to, but not including, c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e; f7534cbfac0a9ffa4fa17cacc6e8b6446dae24ee up to, but not including, 5b5228964619b180f366940505b77255b1a03929; 94458781aee6045bd3d0ad4b80b02886b9e2219b up to, but not including, 857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e; 94458781aee6045bd3d0ad4b80b02886b9e2219b up to, but not including, bea3e1d4467bcf292c8e54f080353d556d355e26; 73f7da507d787b489761a0fa280716f84fa32b2f; 76a4c6636a69d69409aa253b049b1be717a539c5; and 11 more ranges | 343fe375a8dd6ee51a193a1c233b999f5ea4d479, 782acde47e127c98a113726e2ff8024bd65c0454, c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e, 5b5228964619b180f366940505b77255b1a03929, 857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e, bea3e1d4467bcf292c8e54f080353d556d355e26 |
| Linux | Linux Kernel | 5.4.297 up to, but not including, 5.5; 5.10.241 up to, but not including, 5.11; 5.15.190 up to, but not including, 5.15.200; 6.1.149 up to, but not including, 6.1.163; 6.6.103 up to, but not including, 6.6.124; 6.12.43 up to, but not including, 6.12.70; 6.15.11 up to, but not including, 6.16; 6.16.2 up to, but not including, 6.17.3 | 5.5, 5.11, 5.15.200, 6.1.163, 6.6.124, 6.12.70 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.1 | High | CNA |
| CVSS 3.1 | 7.1 | High | NVD |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/343fe375a8dd6ee51a193a1c233b999f5ea4d479
- git.kernel.org/stable/c/5b5228964619b180f366940505b77255b1a03929
- git.kernel.org/stable/c/782acde47e127c98a113726e2ff8024bd65c0454
- git.kernel.org/stable/c/857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e
- git.kernel.org/stable/c/bea3e1d4467bcf292c8e54f080353d556d355e26
- git.kernel.org/stable/c/c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e
Recent Out-of-bounds Read vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Spotted an error? Tell us.