CVE-2025-38713 hfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()

What is CVE-2025-38713?

CVE-2025-38713 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 4 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

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

The hfsplus_readdir() method is capable to crash by calling hfsplus_uni2asc():

[ 667.121659][ T9805] ================================================================== [ 667.122651][ T9805] BUG: KASAN: slab-out-of-bounds in hfsplus_uni2asc+0x902/0xa10 [ 667.123627][ T9805] Read of size 2 at addr ffff88802592f40c by task repro/9805 [ 667.124578][ T9805] [ 667.124876][ T9805] CPU: 3 UID: 0 PID: 9805 Comm: repro Not tainted 6.16.0-rc3 #1 PREEMPT(full) [ 667.124886][ T9805] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 667.124890][ T9805] Call Trace: [ 667.124893][ T9805] <TASK> [ 667.124896][ T9805] dump_stack_lvl+0x10e/0x1f0 [ 667.124911][ T9805] print_report+0xd0/0x660 [ 667.124920][ T9805] ? __virt_addr_valid+0x81/0x610 [ 667.124928][ T9805] ? __phys_addr+0xe8/0x180 [ 667.124934][ T9805] ? hfsplus_uni2asc+0x902/0xa10 [ 667.124942][ T9805] kasan_report+0xc6/0x100 [ 667.124950][ T9805] ? hfsplus_uni2asc+0x902/0xa10 [ 667.124959][ T9805] hfsplus_uni2asc+0x902/0xa10 [ 667.124966][ T9805] ? hfsplus_bnode_read+0x14b/0x360 [ 667.124974][ T9805] hfsplus_readdir+0x845/0xfc0 [ 667.124984][ T9805] ? __pfx_hfsplus_readdir+0x10/0x10 [ 667.124994][ T9805] ? stack_trace_save+0x8e/0xc0 [ 667.125008][ T9805] ? iterate_dir+0x18b/0xb20 [ 667.125015][ T9805] ? trace_lock_acquire+0x85/0xd0 [ 667.125022][ T9805] ? lock_acquire+0x30/0x80 [ 667.125029][ T9805] ? iterate_dir+0x18b/0xb20 [ 667.125037][ T9805] ? down_read_killable+0x1ed/0x4c0 [ 667.125044][ T9805] ? putname+0x154/0x1a0 [ 667.125051][ T9805] ? __pfx_down_read_killable+0x10/0x10 [ 667.125058][ T9805] ? apparmor_file_permission+0x239/0x3e0 [ 667.125069][ T9805] iterate_dir+0x296/0xb20 [ 667.125076][ T9805] __x64_sys_getdents64+0x13c/0x2c0 [ 667.125084][ T9805] ? __pfx___x64_sys_getdents64+0x10/0x10 [ 667.125091][ T9805] ? __x64_sys_openat+0x141/0x200 [ 667.125126][ T9805] ? __pfx_filldir64+0x10/0x10 [ 667.125134][ T9805] ? do_user_addr_fault+0x7fe/0x12f0 [ 667.125143][ T9805] do_syscall_64+0xc9/0x480 [ 667.125151][ T9805] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 667.125158][ T9805] RIP: 0033:0x7fa8753b2fc9 [ 667.125164][ T9805] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 48 [ 667.125172][ T9805] RSP: 002b:00007ffe96f8e0f8 EFLAGS: 00000217 ORIG_RAX: 00000000000000d9 [ 667.125181][ T9805] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa8753b2fc9 [ 667.125185][ T9805] RDX: 0000000000000400 RSI: 00002000000063c0 RDI: 0000000000000004 [ 667.125190][ T9805] RBP: 00007ffe96f8e110 R08: 00007ffe96f8e110 R09: 00007ffe96f8e110 [ 667.125195][ T9805] R10: 0000000000000000 R11: 0000000000000217 R12: 0000556b1e3b4260 [ 667.125199][ T9805] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 667.125207][ T9805] </TASK> [ 667.125210][ T9805] [ 667.145632][ T9805] Allocated by task 9805: [ 667.145991][ T9805] kasan_save_stack+0x20/0x40 [ 667.146352][ T9805] kasan_save_track+0x14/0x30 [ 667.146717][ T9805] __kasan_kmalloc+0xaa/0xb0 [ 667.147065][ T9805] __kmalloc_noprof+0x205/0x550 [ 667.147448][ T9805] hfsplus_find_init+0x95/0x1f0 [ 667.147813][ T9805] hfsplus_readdir+0x220/0xfc0 [ 667.148174][ T9805] iterate_dir+0x296/0xb20 [ 667.148549][ T9805] __x64_sys_getdents64+0x13c/0x2c0 [ 667.148937][ T9805] do_syscall_64+0xc9/0x480 [ 667.149291][ T9805] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 667.149809][ T9805] [ 667.150030][ T9805] The buggy address belongs to the object at ffff88802592f000 [ 667.150030][ T9805] which belongs to the cache kmalloc-2k of size 2048 [ 667.151282][ T9805] The buggy address is located 0 bytes to the right of [ 667.151282][ T9805] allocated 1036-byte region [ffff88802592f000, ffff88802592f40c) [ 667.1 ---truncated---

Weakness: CWE-125

Which versions are affected by CVE-2025-38713?

It affects 2 products.

Products include Debian Debian Linux, Linux kernel.

How do I fix CVE-2025-38713?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2025-38713 being exploited?

There is no known exploitation of CVE-2025-38713 in the wild and no public exploit code.

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All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2025-38713, DEBIAN-CVE-2025-38713, GHSA-f84m-84r4-h992, ROOT-OS-DEBIAN-11-CVE-2025-38713, ROOT-OS-DEBIAN-12-CVE-2025-38713, ROOT-OS-UBUNTU-2204-CVE-2025-38713 and 2 more.