Vulnerability Details CVE-2025-71123
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix string copying in parse_apply_sb_mount_options()
strscpy_pad() can't be used to copy a non-NUL-term string into a NUL-term
string of possibly bigger size. Commit 0efc5990bca5 ("string.h: Introduce
memtostr() and memtostr_pad()") provides additional information in that
regard. So if this happens, the following warning is observed:
strnlen: detected buffer overflow: 65 byte read of buffer size 64
WARNING: CPU: 0 PID: 28655 at lib/string_helpers.c:1032 __fortify_report+0x96/0xc0 lib/string_helpers.c:1032
Modules linked in:
CPU: 0 UID: 0 PID: 28655 Comm: syz-executor.3 Not tainted 6.12.54-syzkaller-00144-g5f0270f1ba00 #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__fortify_report+0x96/0xc0 lib/string_helpers.c:1032
Call Trace:
<TASK>
__fortify_panic+0x1f/0x30 lib/string_helpers.c:1039
strnlen include/linux/fortify-string.h:235 [inline]
sized_strscpy include/linux/fortify-string.h:309 [inline]
parse_apply_sb_mount_options fs/ext4/super.c:2504 [inline]
__ext4_fill_super fs/ext4/super.c:5261 [inline]
ext4_fill_super+0x3c35/0xad00 fs/ext4/super.c:5706
get_tree_bdev_flags+0x387/0x620 fs/super.c:1636
vfs_get_tree+0x93/0x380 fs/super.c:1814
do_new_mount fs/namespace.c:3553 [inline]
path_mount+0x6ae/0x1f70 fs/namespace.c:3880
do_mount fs/namespace.c:3893 [inline]
__do_sys_mount fs/namespace.c:4103 [inline]
__se_sys_mount fs/namespace.c:4080 [inline]
__x64_sys_mount+0x280/0x300 fs/namespace.c:4080
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x64/0x140 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Since userspace is expected to provide s_mount_opts field to be at most 63
characters long with the ending byte being NUL-term, use a 64-byte buffer
which matches the size of s_mount_opts, so that strscpy_pad() does its job
properly. Return with error if the user still managed to provide a
non-NUL-term string here.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 20.2%
CVSS Severity
CVSS v3 Score 7.8
Products affected by CVE-2025-71123
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cpe:2.3:o:linux:linux_kernel:5.10.246
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cpe:2.3:o:linux:linux_kernel:5.10.247
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cpe:2.3:o:linux:linux_kernel:5.4.301
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cpe:2.3:o:linux:linux_kernel:5.4.302
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cpe:2.3:o:linux:linux_kernel:6.1.158
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cpe:2.3:o:linux:linux_kernel:6.1.159
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cpe:2.3:o:linux:linux_kernel:6.12.54
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cpe:2.3:o:linux:linux_kernel:6.12.55
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cpe:2.3:o:linux:linux_kernel:6.12.56
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cpe:2.3:o:linux:linux_kernel:6.12.57
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cpe:2.3:o:linux:linux_kernel:6.12.58
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cpe:2.3:o:linux:linux_kernel:6.12.59
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cpe:2.3:o:linux:linux_kernel:6.12.60
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cpe:2.3:o:linux:linux_kernel:6.12.61
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cpe:2.3:o:linux:linux_kernel:6.12.62
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cpe:2.3:o:linux:linux_kernel:6.12.63
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cpe:2.3:o:linux:linux_kernel:6.17.10
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cpe:2.3:o:linux:linux_kernel:6.17.11
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cpe:2.3:o:linux:linux_kernel:6.17.12
-
cpe:2.3:o:linux:linux_kernel:6.17.13
-
cpe:2.3:o:linux:linux_kernel:6.17.4
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cpe:2.3:o:linux:linux_kernel:6.17.5
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cpe:2.3:o:linux:linux_kernel:6.17.6
-
cpe:2.3:o:linux:linux_kernel:6.17.7
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cpe:2.3:o:linux:linux_kernel:6.17.8
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cpe:2.3:o:linux:linux_kernel:6.17.9
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cpe:2.3:o:linux:linux_kernel:6.18
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cpe:2.3:o:linux:linux_kernel:6.18.1
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cpe:2.3:o:linux:linux_kernel:6.18.2
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cpe:2.3:o:linux:linux_kernel:6.19
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cpe:2.3:o:linux:linux_kernel:6.6.114
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cpe:2.3:o:linux:linux_kernel:6.6.115
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cpe:2.3:o:linux:linux_kernel:6.6.116
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cpe:2.3:o:linux:linux_kernel:6.6.117
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cpe:2.3:o:linux:linux_kernel:6.6.118
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cpe:2.3:o:linux:linux_kernel:6.6.119