CVE-2026-98207

Received Received - Intake

BaseFortify

Publication date: 2026-10-06

Last updated on: 2026-10-19

Assigner: kernel.org

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-06

Last Modified

2026-10-19

Generated

2026-10-19

AI Q&A

2026-10-06

EPSS Evaluated

2026-10-18

NVD

CVE-2026-98207

EUVD

EUVD-2026-93135

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	061c6c847eeb11743e489a16e907b41c6f9042b6
Linux	Linux	061c6c847eeb11743e489a16e907b41c6f9042b6
Linux	Linux	061c6c847eeb11743e489a16e907b41c6f9042b6
Linux	Linux	061c6c847eeb11743e489a16e907b41c6f9042b6
Linux	Linux	061c6c847eeb11743e489a16e907b41c6f9042b6
Linux	Linux	061c6c847eeb11743e489a16e907b41c6f9042b6
Linux	Linux	061c6c847eeb11743e489a16e907b41c6f9042b6
Linux	Linux	061c6c847eeb11743e489a16e907b41c6f9042b6
Linux	Linux	2.6.37

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a Linux kernel vulnerability affecting MMC-over-SPI systems. It involves incorrect accounting of transferred bytes during CRC error recovery. When a CRC error occurs mid-transfer, the system retries the operation but fails to reset the byte counter. This causes the final transfer report to show more bytes than were actually sent, potentially exceeding the expected transfer size.

Detection Guidance

This vulnerability is specific to the Linux kernel's MMC SPI driver and may not have direct network detection methods. Monitor kernel logs for MMC SPI CRC errors or retry events using 'dmesg | grep -i mmc_spi' or 'journalctl -k | grep -i mmc_spi'.

Impact Analysis

The impact is likely limited to systems using MMC-over-SPI with multi-block transfers. It may cause incorrect data accounting, where applications or systems believe more data was transferred than actually occurred. This could lead to data corruption or unexpected behavior in storage operations.

Compliance Impact

This vulnerability affects data integrity in MMC-over-SPI systems by causing incorrect byte accounting during multi-block transfers. While it does not directly impact GDPR or HIPAA compliance, it could lead to inaccurate data transfer records, which may affect audit trails or data processing logs required by these regulations.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for this MMC SPI CRC error handling issue. Check your distribution's security advisories for kernel updates addressing CVE-2026-98207.

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