CVE-2026-98207

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.