CVE-2025-40082

CVE-2025-40082 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

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.

Frequently asked questions

What is CVE-2025-40082?
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.
How severe is CVE-2025-40082?
CVE-2025-40082 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2025-40082 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-40082?
CVE-2025-40082 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-40082?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-40082 have an EU (EUVD) identifier?
Yes. CVE-2025-40082 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-36446.
When was CVE-2025-40082 published?
CVE-2025-40082 was published on 2025-10-28 and last updated on 2026-06-17.

References

Affected products (1)

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