Linux Kernel CVE-2026-46077

The vulnerability resides in the Linux kernel's crypto subsystem driver for the Atmel Triple DES (TDES) hardware accelerator (drivers/crypto/atmel-tdes.c), present since Linux 3.6. On non-coherent DMA platforms - where the CPU cache and DMA memory are not automatically synchronized - correct operation requires explicit cache maintenance calls. Specifically, dma_sync_single_for_cpu() must be called before the CPU reads DMA output to invalidate stale cache lines, while dma_sync_single_for_device() is the correct call before the device writes (not reads). By using the device-direction sync on output buffers, the driver skips the required cache invalidation, leaving the CPU to read whatever was previously cached at that address rather than the fresh DMA output. Affected hardware targets include Atmel AT91 and SAMA5 SoC families running ARM cores, which commonly employ non-coherent DMA. The CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* covers the Linux kernel broadly, with the affected range starting from commit 13802005d8f2 onward through specific stable-branch backport boundaries. The CWE is not formally assigned, but this maps to improper resource synchronization (analogous to CWE-362 or CWE-664) at the hardware/software cache coherency boundary.