CVE-2026-72047

Description

In the Linux kernel, the following vulnerability has been resolved: ieee802154: ca8210: fix pointer truncation in kfifo on 64-bit ca8210_test_int_driver_write() and ca8210_test_int_user_read() exchange a kmalloc'd buffer pointer through a struct kfifo, but pass a literal '4' as the byte count to kfifo_in()/kfifo_out(). This is correct on 32-bit (pointer = 4 bytes), but on 64-bit only the low 4 bytes of the 8-byte pointer are written into the FIFO. The reader then reads back 4 bytes into an 8-byte local pointer variable, leaving the upper 4 bytes uninitialized stack data. The first dereference of the reconstructed pointer (fifo_buffer[1]) accesses an arbitrary kernel address and generally results in an oops. Use sizeof(fifo_buffer) so the byte count matches pointer width on every architecture. The driver has no architecture restriction in Kconfig, so any 64-bit build with CONFIG_IEEE802154_CA8210_DEBUGFS=y is exposed. Issue has been latent since the driver was added in 2017 because it is most commonly deployed on 32-bit MCUs. Found via a custom Coccinelle semantic patch hunting for short-byte kfifo I/O on byte-mode kfifos used to shuttle pointers.

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

References

• https://git.kernel.org/stable/c/093aacb0c56d5c693e3169a0224062e77c3fd0c0
• https://git.kernel.org/stable/c/1fe2643d0b24ca3cdd61a31a45c2d3233dc6cbfe
• https://git.kernel.org/stable/c/2059c28bd725beded01277cdf1f67be33e714323
• https://git.kernel.org/stable/c/2c1664ccfae653979b38788211240b5a1ee317ed
• https://git.kernel.org/stable/c/65dc342274a01616f5c17105f7360a3b4bfd7a3d
• https://git.kernel.org/stable/c/6d7f7bcf225b2d566176bf6229dbd1252940cb3c
• https://git.kernel.org/stable/c/87dab14a4f68895d6f4d798e6ee3556cd64e8c72
• https://git.kernel.org/stable/c/d8ce67fa6a5e6929f5414e933ff9665176c2bce6