CVE-2026-72134 spi: imx: reconfigure for PIO when DMA cannot be started
A Linux kernel SPI driver bug causes data corruption and TPM failure when DMA initialization fails, requiring a patch to correctly reconfigure for PIO mode.
- 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-2026-72134?
CVE-2026-72134 is a high-severity vulnerability in Linux, published on 15 Aug 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:
spi: imx: reconfigure for PIO when DMA cannot be started
When spi_imx_can_dma() selects DMA, the ECSPI is configured for DMA: spi_imx_setupxfer() sets CTRL.SMC and clears dynamic_burst, and spi_imx_dma_transfer() programs the dynamic-burst BURST_LENGTH and the SDMA watermarks.
If the DMA descriptor cannot be prepared (dmaengine_prep_slave_single() returns NULL), the transfer is failed with SPI_TRANS_FAIL_NO_START and falls back to PIO. The dynamic-burst DMA path uses its own bounce buffers instead of the SPI core's mapping, so xfer->{tx,rx}_sg_mapped are not set and the core's DMA->PIO retry is skipped; the driver falls back to PIO internally. But none of the DMA-mode configuration is undone, so the PIO transfer runs with CTRL.SMC set, the wrong burst length and dynamic_burst cleared, and the transferred data is corrupted.
This is easily hit on i.MX8MP boards that describe ECSPI DMA in the device tree but run SDMA on ROM firmware (no external sdma-imx7d.bin): every ECSPI DMA prepare fails. An Infineon SLB9670 TPM on ECSPI1 then returns shifted TPM2_GetCapability data, is flagged "field failure mode", /dev/tpmrm0 is never created.
Set controller->fallback before re-running spi_imx_setupxfer() so the ECSPI is reconfigured exactly like a normal PIO transfer. With controller->fallback set, spi_imx_setupxfer() sees spi_imx_can_dma() return false, so it clears spi_imx->usedma and reprograms the controller (clears CTRL.SMC, restores dynamic_burst and the PIO burst length). No explicit spi_imx->usedma = false is needed: setupxfer() already updates it from the can_dma() result.
Which versions are affected by CVE-2026-72134?
How do I fix CVE-2026-72134?
Apply the vendor's patch.
Is CVE-2026-72134 being exploited?
There is no known exploitation of CVE-2026-72134 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-72134, GHSA-pv8g-5qg3-q63w, UBUNTU-CVE-2026-72134.