Bug 2507107 (CVE-2026-64504) - CVE-2026-64504 kernel: iio: accel: bmc150: clamp the device-reported FIFO frame count
Summary: CVE-2026-64504 kernel: iio: accel: bmc150: clamp the device-reported FIFO fra...
Keywords:
Status: NEW
Alias: CVE-2026-64504
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
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Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-25 10:05 UTC by OSIDB Bzimport
Modified: 2026-07-30 05:36 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-07-25 10:05:20 UTC
In the Linux kernel, the following vulnerability has been resolved:

iio: accel: bmc150: clamp the device-reported FIFO frame count

__bmc150_accel_fifo_flush() copies the number of samples the device
reports in its hardware FIFO into an on-stack buffer

	u16 buffer[BMC150_ACCEL_FIFO_LENGTH * 3];

which is sized for at most BMC150_ACCEL_FIFO_LENGTH (32) samples. The
frame count is read from the FIFO_STATUS register and only masked to its
7 valid bits:

	count = val & 0x7F;

so it can be 0..127. The only other limit applied to it is the optional
caller-supplied sample budget:

	if (samples && count > samples)
		count = samples;

which does not constrain count on the flush-all path (samples == 0), and
leaves it well above 32 whenever samples is larger. count samples are
then transferred into buffer[]:

	bmc150_accel_fifo_transfer(data, (u8 *)buffer, count);

bmc150_accel_fifo_transfer() reads count * 6 bytes through regmap, so a
malfunctioning, malicious or counterfeit accelerometer (or an attacker
tampering with the I2C/SPI bus) that reports up to 127 frames writes up
to 762 bytes into the 192-byte buffer: a stack out-of-bounds write of up
to 570 bytes that clobbers the stack canary, saved registers and the
return address.

Clamp count to BMC150_ACCEL_FIFO_LENGTH, the number of samples buffer[]
is sized for, before the transfer, mirroring the watermark clamp already
done in bmc150_accel_set_watermark(). A well-formed flush reports at most
BMC150_ACCEL_FIFO_LENGTH frames, so legitimate devices are unaffected.


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