CVE-2026-90012 spi: Fix DMA mapping ownership on partial map failure
A null pointer dereference in the Linux kernel SPI driver can cause a system crash when DMA mapping fails partially.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90012?
CVE-2026-90012 is a critical vulnerability in Linux, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
spi: Fix DMA mapping ownership on partial map failure
If RX mapping fails after TX mapping succeeds, __spi_map_msg() unmaps TX but leaves tx_sg_mapped set. If TX mapping fails on a later transfer, mappings created for earlier transfers remain active.
In both cases, cur_{tx,rx}_dma_dev have not yet been updated because they are assigned only after every transfer has been mapped. The subsequent spi_unmap_msg() may therefore unmap the TX mapping again or release earlier mappings using a NULL or stale device. Using a NULL device can trigger an oops. An empty SG table does not prevent the NULL dereference because dma_unmap_sg_attrs() accesses the device before checking the entry count.
Publish both mapping devices before mapping starts and unwind all failures through __spi_unmap_msg(). This clears the mapping flags and releases each mapping once with the device that created it.
Publishing the devices before the loop also refreshes them when no transfer needs mapping. No mapping flag is set in that case, so current users do not use the pointers as mapping owners.
Which versions are affected by CVE-2026-90012?
How do I fix CVE-2026-90012?
Apply the vendor's patch.
Is CVE-2026-90012 being exploited?
There is no known exploitation of CVE-2026-90012 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90012, DEBIAN-CVE-2026-90012, GHSA-xm4q-v74w-px7x, UBUNTU-CVE-2026-90012.