fs: udf: fix OOB read in lengthAllocDescs handling
When parsing Allocation Extent Descriptor, lengthAllocDescs comes from
on-disk data and must be validated against the block size. Crafted or
corrupted images may set lengthAllocDescs so that the total descriptor
length (sizeof(allocExtDesc) + lengthAllocDescs) exceeds the buffer,
leading udf_update_tag() to call crc_itu_t() on out-of-bounds memory and
trigger a KASAN use-after-free read.
BUG: KASAN: use-after-free in crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60
Read of size 1 at addr ffff888041e7d000 by task syz-executor317/5309
CPU: 0 UID: 0 PID: 5309 Comm: syz-executor317 Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60
udf_update_tag+0x70/0x6a0 fs/udf/misc.c:261
udf_write_aext+0x4d8/0x7b0 fs/udf/inode.c:2179
extent_trunc+0x2f7/0x4a0 fs/udf/truncate.c:46
udf_truncate_tail_extent+0x527/0x7e0 fs/udf/truncate.c:106
udf_release_file+0xc1/0x120 fs/udf/file.c:185
__fput+0x23f/0x880 fs/file_table.c:431
task_work_run+0x24f/0x310 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa2f/0x28e0 kernel/exit.c:939
do_group_exit+0x207/0x2c0 kernel/exit.c:1088
__do_sys_exit_group kernel/exit.c:1099 [inline]
__se_sys_exit_group kernel/exit.c:1097 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097
x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Validate the computed total length against epos->bh->b_size.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4379-1 | linux-6.1 security update |
Debian DLA |
DLA-4404-1 | linux security update |
Debian DSA |
DSA-6053-1 | linux security update |
Ubuntu USN |
USN-8029-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8030-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8033-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-3 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8034-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Ubuntu USN |
USN-8033-4 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8029-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8034-2 | Linux kernel (NVIDIA Tegra IGX) vulnerabilities |
Ubuntu USN |
USN-8048-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-8033-6 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8033-7 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-8 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-8029-3 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8095-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8095-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8100-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8095-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8095-4 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8125-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8126-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8095-5 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8141-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8163-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8165-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8163-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8243-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8261-1 | Linux kernel (Xilinx) vulnerabilities |
Mon, 01 Dec 2025 06:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
Wed, 29 Oct 2025 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Wed, 29 Oct 2025 11:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Wed, 29 Oct 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Tue, 28 Oct 2025 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: fs: udf: fix OOB read in lengthAllocDescs handling When parsing Allocation Extent Descriptor, lengthAllocDescs comes from on-disk data and must be validated against the block size. Crafted or corrupted images may set lengthAllocDescs so that the total descriptor length (sizeof(allocExtDesc) + lengthAllocDescs) exceeds the buffer, leading udf_update_tag() to call crc_itu_t() on out-of-bounds memory and trigger a KASAN use-after-free read. BUG: KASAN: use-after-free in crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60 Read of size 1 at addr ffff888041e7d000 by task syz-executor317/5309 CPU: 0 UID: 0 PID: 5309 Comm: syz-executor317 Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60 udf_update_tag+0x70/0x6a0 fs/udf/misc.c:261 udf_write_aext+0x4d8/0x7b0 fs/udf/inode.c:2179 extent_trunc+0x2f7/0x4a0 fs/udf/truncate.c:46 udf_truncate_tail_extent+0x527/0x7e0 fs/udf/truncate.c:106 udf_release_file+0xc1/0x120 fs/udf/file.c:185 __fput+0x23f/0x880 fs/file_table.c:431 task_work_run+0x24f/0x310 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xa2f/0x28e0 kernel/exit.c:939 do_group_exit+0x207/0x2c0 kernel/exit.c:1088 __do_sys_exit_group kernel/exit.c:1099 [inline] __se_sys_exit_group kernel/exit.c:1097 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Validate the computed total length against epos->bh->b_size. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. | |
| Title | fs: udf: fix OOB read in lengthAllocDescs handling | |
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:41:23.827Z
Reserved: 2025-04-16T07:20:57.154Z
Link: CVE-2025-40044
No data.
Status : Deferred
Published: 2025-10-28T12:15:38.453
Modified: 2026-04-15T00:35:42.020
Link: CVE-2025-40044
OpenCVE Enrichment
Updated: 2025-10-29T10:58:01Z
No weakness.
Debian DLA
Debian DSA
Ubuntu USN