CVE-2026-89440

Received Received - Intake

Linux Kernel mmc: via-sdmmc Interrupt Use-After-Free

Publication date: 2026-09-11

Last updated on: 2026-09-14

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: mmc: via-sdmmc: stop card-detect handling on probe failure request_irq() registers the SD card-detect interrupt and the probe enables it before mmc_add_host() runs. If mmc_add_host() fails, the error path only unmaps the registers and returns: the interrupt stays registered, so the handler keeps running against the host once it is freed. via_sdc_isr() dereferences sdhost and its MMIO base and schedules carddet_work, which via_sdc_card_detect() also runs against freed memory through its container_of() dereference. Add a probe-error path that disables and frees the interrupt and cancels carddet_work before unmapping. carddet_work can re-enable the device interrupt via via_reset_pcictrl(), which restores PCIINTCTRL, so mask it again after cancelling the work. This issue was found by an in-house static analysis tool and confirmed by manual code review.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-11

Last Modified

2026-09-14

Generated

2026-10-02

AI Q&A

2026-09-12

EPSS Evaluated

2026-10-01

NVD

CVE-2026-89440

EUVD

EUVD-2026-76346

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves improper handling of the SD card-detect interrupt during the probe process. When mmc_add_host() fails, the error path does not properly clean up the registered interrupt, leaving it active. This can lead to a use-after-free scenario where the interrupt handler continues to run against freed memory, potentially causing system instability or crashes.

Detection Guidance

This vulnerability is specific to the Linux kernel's mmc subsystem and does not have a direct network detection method. It involves a kernel driver issue where an interrupt handler may run against freed memory. Detection requires checking kernel logs for mmc-related errors or crashes, particularly during SD card initialization or probe failures.

Impact Analysis

If exploited, this vulnerability could cause kernel crashes, data corruption, or unauthorized access to system memory. Users might experience system freezes, unexpected reboots, or security breaches depending on the affected system's role and configuration.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to a Linux kernel driver issue involving memory corruption during SD card detection. No evidence suggests data exposure or privacy violations typical of compliance violations.

Mitigation Strategies

Apply the latest Linux kernel updates or patches that address this issue. If you are using a vulnerable kernel version, avoid using the via-sdmmc driver or disable SD card detection interrupts until patched. Monitor kernel logs for mmc-related errors as a sign of exploitation.

Hi! I’m here to help you understand CVE-2026-89440. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70