CVE-2026-97502
Received Received - Intake

NULL Pointer Dereference in Linux Kernel MMC Driver

Vulnerability report for CVE-2026-97502, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-24

Last updated on: 2026-10-03

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: mmc: davinci: avoid NULL deref of host->data in IRQ handler mmc_davinci_irq() returns early only when both host->cmd and host->data are NULL: if (host->cmd == NULL && host->data == NULL) { ... return IRQ_NONE; } So we may legitimately reach the rest of the handler with host->data == NULL (and therefore data == NULL). The DATDNE branch already guards against this with an explicit "if (data != NULL)" check, but the subsequent TOUTRD ("read data timeout") and CRCWR/CRCRD ("data CRC error") branches dereference data unconditionally: if (qstatus & MMCST0_TOUTRD) { data->error = -ETIMEDOUT; <-- NULL deref ... davinci_abort_data(host, data); } if (qstatus & (MMCST0_CRCWR | MMCST0_CRCRD)) { data->error = -EILSEQ; <-- NULL deref ... } If either bit is set in qstatus while host->data is NULL, the kernel will crash inside the IRQ handler. smatch flags this: drivers/mmc/host/davinci_mmc.c:933 mmc_davinci_irq() error: we previously assumed 'data' could be null (see line 914) Gate both branches on a non-NULL data, matching the existing pattern used by the DATDNE branch. No functional change for callers where data is non-NULL, which is the only case in which these branches did meaningful work before this change.

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Meta Information

Published
2026-09-24
Last Modified
2026-10-03
Generated
2026-10-15
AI Q&A
2026-09-25
EPSS Evaluated
2026-10-13
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is in the Linux kernel's MMC (MultiMediaCard) driver for Davinci devices. It involves a NULL pointer dereference in the IRQ handler where the code fails to check if host->data is NULL before accessing it. This can lead to a kernel crash if certain error conditions occur while processing MMC commands.

Detection Guidance

This vulnerability is specific to the Linux kernel's MMC (MultiMediaCard) driver for Davinci devices. Detection requires checking the kernel version and the presence of the affected driver code. Examine kernel logs for NULL pointer dereference errors in the MMC subsystem, particularly during IRQ handling. No specific commands are provided in the context.

Impact Analysis

If exploited, this vulnerability could cause a system crash or kernel panic when the affected MMC device encounters specific error conditions. This may result in denial of service, data corruption, or system instability on devices using the Davinci MMC driver in the Linux kernel.

Compliance Impact

This vulnerability is a kernel-level issue in the Linux MMC subsystem that could cause a NULL pointer dereference in the IRQ handler, leading to a kernel crash. It does not directly affect data confidentiality, integrity, or availability in a way that would impact compliance with standards like GDPR or HIPAA. The issue is localized to a specific hardware driver and does not involve data exposure or processing violations.

Mitigation Strategies

Apply the kernel patch that resolves this issue by adding NULL checks in the MMC Davinci IRQ handler. Update to a patched kernel version where the issue is fixed. Monitor kernel logs for related errors and ensure the MMC driver is functioning correctly after updates.

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