Description

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

tracing: Fix oob write in trace_seq_to_buffer()

syzbot reported this bug:
==================================================================
BUG: KASAN: slab-out-of-bounds in trace_seq_to_buffer kernel/trace/trace.c:1830 [inline]
BUG: KASAN: slab-out-of-bounds in tracing_splice_read_pipe+0x6be/0xdd0 kernel/trace/trace.c:6822
Write of size 4507 at addr ffff888032b6b000 by task syz.2.320/7260

CPU: 1 UID: 0 PID: 7260 Comm: syz.2.320 Not tainted 6.15.0-rc1-syzkaller-00301-g3bde70a2c827 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:

__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0xc3/0x670 mm/kasan/report.c:521
kasan_report+0xe0/0x110 mm/kasan/report.c:634
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
__asan_memcpy+0x3c/0x60 mm/kasan/shadow.c:106
trace_seq_to_buffer kernel/trace/trace.c:1830 [inline]
tracing_splice_read_pipe+0x6be/0xdd0 kernel/trace/trace.c:6822
....
==================================================================

It has been reported that trace_seq_to_buffer() tries to copy more data
than PAGE_SIZE to buf. Therefore, to prevent this, we should use the
smaller of trace_seq_used(&iter->seq) and PAGE_SIZE as an argument.

Classification

CVE ID: CVE-2025-37923

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.06% (probability of being exploited)

EPSS Percentile: 17.55% (scored less or equal to compared to others)

EPSS Date: 2025-06-18 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-37923
https://git.kernel.org/stable/c/1a3f9482b50b74fa9421bff8ceecfefd0dc06f8f
https://git.kernel.org/stable/c/441021e5b3c7d9bd1b963590652c415929f3b157
https://git.kernel.org/stable/c/056ebbddb8faf4ddf83d005454dd78fc25c2d897
https://git.kernel.org/stable/c/1f27a3e93b8d674b24b27fcdbc6f72743cd96c0d
https://git.kernel.org/stable/c/c5d2b66c5ef5037b4b4360e5447605ff00ba1bd4
https://git.kernel.org/stable/c/f5178c41bb43444a6008150fe6094497135d07cb

Timeline