CVE-2026-89441 mmc: via-sdmmc: cancel card-detect work on remove
A use-after-free vulnerability in the Linux kernel's via-sdmmc driver allows attackers to cause memory corruption or system crashes by triggering card detection during device removal.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89441?
CVE-2026-89441 is a high-severity use after free vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
mmc: via-sdmmc: cancel card-detect work on remove
Disabling the device interrupt and freeing the IRQ prevents new card-detect work from being queued, but carddet_work already queued by the handler can still run after via_sd_remove() returns. via_sdc_card_detect() recovers the host through container_of() and dereferences its MMIO base; once remove() returns the host can be freed, so that work would touch freed memory.
Cancel carddet_work after freeing the IRQ and before cancelling finish_bh_work, which the card-detect handler can also queue. carddet_work can re-enable the interrupt through via_reset_pcictrl(); mask it again afterwards.
This issue was found by an in-house static analysis tool and confirmed by manual code review.
Which versions are affected by CVE-2026-89441?
How do I fix CVE-2026-89441?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-89441 being exploited?
There is no known exploitation of CVE-2026-89441 in the wild and no public exploit code.
Sources
Also known as AZL-100761, BELL-CVE-2026-89441, DEBIAN-CVE-2026-89441, GHSA-6v98-4pph-jq73, UBUNTU-CVE-2026-89441.