Description
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix use-after-free read in ext4_find_extent for bigalloc + inline
Syzbot found the following issue:
loop0: detected capacity change from 0 to 2048
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none.
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931
Read of size 4 at addr ffff888073644750 by task syz-executor420/5067
CPU: 0 PID: 5067 Comm: syz-executor420 Not tainted 6.2.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
print_address_description+0x74/0x340 mm/kasan/report.c:306
print_report+0x107/0x1f0 mm/kasan/report.c:417
kasan_report+0xcd/0x100 mm/kasan/report.c:517
ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]
ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931
ext4_clu_mapped+0x117/0x970 fs/ext4/extents.c:5809
ext4_insert_delayed_block fs/ext4/inode.c:1696 [inline]
ext4_da_map_blocks fs/ext4/inode.c:1806 [inline]
ext4_da_get_block_prep+0x9e8/0x13c0 fs/ext4/inode.c:1870
ext4_block_write_begin+0x6a8/0x2290 fs/ext4/inode.c:1098
ext4_da_write_begin+0x539/0x760 fs/ext4/inode.c:3082
generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772
ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285
ext4_file_write_iter+0x1d0/0x18f0
call_write_iter include/linux/fs.h:2186 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x7dc/0xc50 fs/read_write.c:584
ksys_write+0x177/0x2a0 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f4b7a9737b9
RSP: 002b:00007ffc5cac3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b7a9737b9
RDX: 00000000175d9003 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 00007f4b7a933050 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000079f R11: 0000000000000246 R12: 00007f4b7a9330e0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Above issue is happens when enable bigalloc and inline data feature. As
commit 131294c35ed6 fixed delayed allocation bug in ext4_clu_mapped for
bigalloc + inline. But it only resolved issue when has inline data, if
inline data has been converted to extent(ext4_da_convert_inline_data_to_extent)
before writepages, there is no EXT4_STATE_MAY_INLINE_DATA flag. However
i_data is still store inline data in this scene. Then will trigger UAF
when find extent.
To resolve above issue, there is need to add judge "ext4_has_inline_data(inode)"
in ext4_clu_mapped().
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 4.19.270 – < 4.19.271, 5.4.229 – < 5.4.243, 5.10.163 – < 5.10.180, 5.15.87 – < 5.15.111, 6.1.4 – < 6.1.28, 6.0.18 – < 6.1, 6.2 | 4.19.271 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.3.7-1 | — |
| Debian 13 | linux | 6.3.7-1 | — |
| Debian 12 | linux | 6.1.37-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1022.24 | — |
| Ubuntu 24.04 LTS | linux-riscv +8 | No fix yet | — |
| Ubuntu 22.04 LTS | linux | 5.15.0-79.86 | — |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1042.47 | — |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1045.52 | — |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1045.52.1 | — |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1039.47 | — |
| Ubuntu 22.04 LTS | linux-gke +1 | 5.15.0-1039.44 | — |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1025.30 | — |
| Ubuntu 22.04 LTS | linux-ibm +1 | 5.15.0-1035.38 | — |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1037.42 | — |
| Ubuntu 22.04 LTS | linux-lowlatency | 5.15.0-79.88 | — |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1030.30 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1016.16 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1002.2 | — |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1040.46 | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1025.29 | — |
| Ubuntu 20.04 LTS | linux | 5.4.0-162.179 | — |
| Ubuntu 20.04 LTS | linux-aws | 5.4.0-1109.118 | — |
| Ubuntu 20.04 LTS | linux-aws-5.15 | 5.15.0-1041.46~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-azure | 5.4.0-1115.122 | — |
| Ubuntu 20.04 LTS | linux-azure-5.15 | 5.15.0-1045.52~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-bluefield | 5.4.0-1070.76 | — |
| Ubuntu 20.04 LTS | linux-gcp | 5.4.0-1112.121 | — |
| Ubuntu 20.04 LTS | linux-gcp-5.15 | 5.15.0-1039.47~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-hwe-5.15 | 5.15.0-79.86~20.04.2 | — |
| Ubuntu 20.04 LTS | linux-ibm | 5.4.0-1056.61 | — |
| Ubuntu 20.04 LTS | linux-ibm-5.15 | 5.15.0-1036.39~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1037.42~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-iot | 5.4.0-1021.22 | — |
| Ubuntu 20.04 LTS | linux-kvm | 5.4.0-1098.104 | — |
| Ubuntu 20.04 LTS | linux-lowlatency-hwe-5.15 | 5.15.0-79.88~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1016.16~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-oracle | 5.4.0-1108.117 | — |
| Ubuntu 20.04 LTS | linux-oracle-5.15 | 5.15.0-1040.46~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-raspi | 5.4.0-1093.104 | — |
| Ubuntu 20.04 LTS | linux-riscv-5.15 | 5.15.0-1038.42~20.04.2 | — |
| Ubuntu 20.04 LTS | linux-xilinx-zynqmp | 5.4.0-1029.33 | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1036.38 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1043.48 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-aws-fips | 5.4.0-1109.118+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1115.122+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips | 5.4.0-1084.93 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-gcp-fips | 5.4.0-1112.121+fips1 | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro 18.04 LTS | linux-aws-5.4 | 5.4.0-1109.118~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-azure-5.4 | 5.4.0-1115.122~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-gcp-5.4 | 5.4.0-1112.121~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-hwe-5.4 | 5.4.0-162.179~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-ibm-5.4 | 5.4.0-1056.61~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-oracle-5.4 | 5.4.0-1108.117~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-raspi-5.4 | 5.4.0-1093.104~18.04.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP5 | kernel-64kb +6 | 5.14.21-150500.55.127.1 | SUSE-SU-2025:4320-1 |
| SLES 15 SP5 | kernel-default-base | 5.14.21-150500.55.127.1.150500.6.61.1 | SUSE-SU-2025:4320-1 |
| SLES 15 SP4 | kernel-64kb +6 | 5.14.21-150400.24.184.1 | SUSE-SU-2025:4111-1 |
| SLES 15 SP4 | kernel-default-base | 5.14.21-150400.24.184.1.150400.24.94.2 | SUSE-SU-2025:4111-1 |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP5 | kernel-default-base | 5.14.21-150500.55.127.1.150500.6.61.1 | SUSE-SU-2025:4320-1 |
| SLES for SAP 15 SP5 | kernel-docs +4 | 5.14.21-150500.55.127.1 | SUSE-SU-2025:4320-1 |
| SLES for SAP 15 SP4 | kernel-default-base | 5.14.21-150400.24.184.1.150400.24.94.2 | SUSE-SU-2025:4111-1 |
| SLES for SAP 15 SP4 | kernel-docs +4 | 5.14.21-150400.24.184.1 | SUSE-SU-2025:4111-1 |
| SLE Micro 5.5 | kernel-default-base | 5.14.21-150500.55.127.1.150500.6.61.1 | SUSE-SU-2025:4320-1 |
| SLE Micro 5.5 | kernel-rt +1 | 5.14.21-150500.13.112.1 | SUSE-SU-2025:4149-1 |
| SLE Micro 5.5 | kernel-source +1 | 5.14.21-150500.55.127.1 | SUSE-SU-2025:4320-1 |
| SLE Micro 5.4 | kernel-default | 5.14.21-150400.24.184.1 | SUSE-SU-2025:4111-1 |
| SLE Micro 5.4 | kernel-default-base | 5.14.21-150400.24.184.1.150400.24.94.2 | SUSE-SU-2025:4111-1 |
| SLE Micro 5.4 | kernel-rt +1 | 5.14.21-150400.15.136.1 | SUSE-SU-2025:4139-1 |
| SLE Micro 5.3 | kernel-default | 5.14.21-150400.24.184.1 | SUSE-SU-2025:4111-1 |
| SLE Micro 5.3 | kernel-default-base | 5.14.21-150400.24.184.1.150400.24.94.2 | SUSE-SU-2025:4111-1 |
| SLE Micro 5.3 | kernel-rt +1 | 5.14.21-150400.15.136.1 | SUSE-SU-2025:4139-1 |
| SLE Live Patching 15 SP5 | kernel-default | 5.14.21-150500.55.127.1 | SUSE-SU-2025:4320-1 |
| SLE Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5_Update_32 | 1-150500.11.3.1 | SUSE-SU-2025:4320-1 |
| SLE Live Patching 15 SP4 | kernel-default | 5.14.21-150400.24.184.1 | SUSE-SU-2025:4111-1 |
| SLE Live Patching 15 SP4 | kernel-livepatch-SLE15-SP4_Update_46 | 1-150400.9.5.1 | SUSE-SU-2025:4111-1 |
| SLE HPC 15 SP5 | kernel-64kb +5 | 5.14.21-150500.55.127.1 | SUSE-SU-2025:4320-1 |
| SLE HPC 15 SP5 | kernel-default-base | 5.14.21-150500.55.127.1.150500.6.61.1 | SUSE-SU-2025:4320-1 |
| SLE HPC 15 SP4 | kernel-64kb +5 | 5.14.21-150400.24.184.1 | SUSE-SU-2025:4111-1 |
| SLE HPC 15 SP4 | kernel-default-base | 5.14.21-150400.24.184.1.150400.24.94.2 | SUSE-SU-2025:4111-1 |
| SUSE Manager Server LTS 4.3 | kernel-default-base | 5.14.21-150400.24.184.1.150400.24.94.2 | SUSE-SU-2025:4111-1 |
| SUSE Manager Server LTS 4.3 | kernel-syms +3 | 5.14.21-150400.24.184.1 | SUSE-SU-2025:4111-1 |
| SUSE Manager Proxy LTS 4.3 | kernel-default-base | 5.14.21-150400.24.184.1.150400.24.94.2 | SUSE-SU-2025:4111-1 |
| SUSE Manager Proxy LTS 4.3 | kernel-syms +2 | 5.14.21-150400.24.184.1 | SUSE-SU-2025:4111-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.1.29-47.49 | 1.0-0.amzn2023 | ALAS2023-2023-184 |
| Amazon Linux 2023 | perf +12 | 6.1.29-47.49.amzn2023 | ALAS2023-2023-184 |
Advisories 6
- WID-SEC-2025-2394 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 9, 2026
- SUSE-SU-2025:4139-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:4149-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:4111-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- ALAS2023-2023-184 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Feb 11, 2026
- SUSE-SU-2025:4320-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://git.kernel.org/stable/c/0ce15000dee0ecd6f235f925a327803e2ef489c6
- https://git.kernel.org/stable/c/a34f6dcb78c654ab905642c1b4e7e5fbb4f0babe
- https://git.kernel.org/stable/c/770b0613637f59f3091dda1ff0c23671a5326b9c
- https://git.kernel.org/stable/c/40566def189c513be2c694681256d7486cc6e368
- https://git.kernel.org/stable/c/96d440bee177669dc0acedca0abd73bae6a9be8b
- https://git.kernel.org/stable/c/11c87c8df2cae1d6be83c07e59fef0792de73482
- https://git.kernel.org/stable/c/14da044725a3ab10affa3566d29c15737c0e67a4
- https://git.kernel.org/stable/c/835659598c67907b98cd2aa57bb951dfaf675c69