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

mmc: spi: reset bytes_xfered before retrying CRC failures

mmc_spi_data_do() updates data->bytes_xfered after each block has been
transferred successfully. If a later block in the same data request
fails with a CRC error, data->bytes_xfered may therefore contain the
number of bytes completed before the failing block.

mmc_spi_request() has a private recovery path for such CRC failures. It
sends STOP_TRANSMISSION, clears data->error and jumps back to
crc_recover to issue the same command and data request again. However,
it does not clear data->bytes_xfered before the retry.

If the retry succeeds, the request is completed with the bytes from the
failed attempt still included in data->bytes_xfered. For a multi-block
request this can make the completed request report more bytes than were
transferred by the successful retry, and can even exceed the request size
when most blocks completed before the CRC error.

This is most likely to be observed on MMC-over-SPI systems where long
multi-block transfers occasionally hit a data CRC error but the
mmc_spi-internal retry succeeds. The data itself is retried, but the
completion accounting is not.

Clear data->bytes_xfered together with data->error before repeating the
request so the final completion reports only the bytes transferred by the
successful attempt.
Published: 2026-10-06
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Tue, 06 Oct 2026 09:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mmc: spi: reset bytes_xfered before retrying CRC failures mmc_spi_data_do() updates data->bytes_xfered after each block has been transferred successfully. If a later block in the same data request fails with a CRC error, data->bytes_xfered may therefore contain the number of bytes completed before the failing block. mmc_spi_request() has a private recovery path for such CRC failures. It sends STOP_TRANSMISSION, clears data->error and jumps back to crc_recover to issue the same command and data request again. However, it does not clear data->bytes_xfered before the retry. If the retry succeeds, the request is completed with the bytes from the failed attempt still included in data->bytes_xfered. For a multi-block request this can make the completed request report more bytes than were transferred by the successful retry, and can even exceed the request size when most blocks completed before the CRC error. This is most likely to be observed on MMC-over-SPI systems where long multi-block transfers occasionally hit a data CRC error but the mmc_spi-internal retry succeeds. The data itself is retried, but the completion accounting is not. Clear data->bytes_xfered together with data->error before repeating the request so the final completion reports only the bytes transferred by the successful attempt.
Title mmc: spi: reset bytes_xfered before retrying CRC failures
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-06T08:44:44.241Z

Reserved: 2026-09-25T10:25:14.325Z

Link: CVE-2026-98207

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-06T09:18:06.843

Modified: 2026-10-06T09:18:06.843

Link: CVE-2026-98207

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.