UBUNTU-CVE-2026-98207: Medium severity ubuntu/linux vulnerability
In the Linux kernel, the following vulnerability has been resolved: mmc: spi: reset bytesxfered before retrying CRC failures mmcspidatado() updates data->bytesxfered after each block has been transferred successfully. If a later block in the same data request fails with a CRC error, data->bytesxfered may therefore contain the number of bytes completed before the failing block. mmcspirequest() has a private recovery path for such CRC failures. It sends STOPTRANSMISSION, clears data->error and jumps back to crcrecover to issue the same command and data request again. However, it does not clear data->bytesxfered before the retry. If the retry succeeds, the request is completed with the bytes from the failed attempt still included in data->bytesxfered. 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 mmcspi-internal retry succeeds. The data itself is retried, but the completion accounting is not. Clear data->bytesxfered together with data->error before repeating the request so the final completion reports only the bytes transferred by the successful attempt.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-aws-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1119.126~20.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1125.134~20.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-fde-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1124.133~20.04.1 - Upgrade
Upgrade
ubuntu/linux-gcp-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1120.130~20.04.1 - Upgrade
Upgrade
ubuntu/linux-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-202.212~20.04.1 - Upgrade
Upgrade
ubuntu/linux-ibm-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1113.117~20.04.1 - Upgrade
Upgrade
ubuntu/linux-intel-iotg-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1114.120~20.04.1 - Upgrade
Upgrade
ubuntu/linux-lowlatency-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-197.207~20.04.1 - Upgrade
Upgrade
ubuntu/linux-nvidia-tegra-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1070.72~20.04.1 - Upgrade
Upgrade
ubuntu/linux-oracle-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1116.122~20.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1113.117~20.04.2 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 5.15.0-202.212 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 5.15.0-1119.126 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 5.15.0-1125.134 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 5.15.0-1120.130 - Upgrade
Upgrade
ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 5.15.0-1115.121 - Upgrade
Upgrade
ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 5.15.0-1102.110 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 5.15.0-1113.117 - Upgrade
Upgrade
ubuntu/linux-intel-iotgto a version that resolves this vulnerability.Fixed in 5.15.0-1114.120 - Upgrade
Upgrade
ubuntu/linux-kvmto a version that resolves this vulnerability.Fixed in 5.15.0-1111.116 - Upgrade
Upgrade
ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 5.15.0-197.207 - Upgrade
Upgrade
ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 5.15.0-1114.115 - Upgrade
Upgrade
ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 5.15.0-1070.72 - Upgrade
Upgrade
ubuntu/linux-nvidia-tegra-igxto a version that resolves this vulnerability.Fixed in 5.15.0-1059.59 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 5.15.0-1116.122 - Upgrade
Upgrade
ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 5.15.0-1103.105 - Upgrade
Upgrade
ubuntu/linux-intel-iot-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1111.115 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1118.127 - Upgrade
Upgrade
ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1119.126+fips1 - Upgrade
Upgrade
ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1125.134+fips1 - Upgrade
Upgrade
ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-202.212+fips1 - Upgrade
Upgrade
ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1120.130+fips1 - Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
In the MMC-over-SPI CRC recovery path, reset data->bytes_xfered together with data->error before retrying the data request, so completion accounting reflects only the successful attempt.
Event History
Frequently Asked Questions
Which systems are most likely to encounter this issue?
MMC-over-SPI systems are the relevant exposure area. The issue is most likely during long multi-block transfers that encounter an occasional data CRC error and then succeed through the driver's internal retry path.
What sequence is required for incorrect byte accounting?
A multi-block request must successfully transfer one or more blocks, then fail on a later block with a CRC error. The MMC SPI driver's retry must then succeed, while retaining the byte count from the failed attempt.
How can operators recognize the problem in logs or instrumentation?
Look for completed multi-block requests reporting more bytes than were transferred by the successful retry. In some cases, the reported completed-byte count can exceed the request size.