CVE-2026-99164: Linux kernel · spi: imx: fix slab corruption from undersized DMA bounce buffers
Affects Linux kernelSource CVE Database V5
Not known to be exploited : upgrade to 2777f6637da02da84c9c1ff92f413ce0f0995084 or 59eb22641f0c526dd064390b11cff99ae87c2858 when convenient.
Data as of 28 Oct 2026, 10:58 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- Patch
- Available – fixed in 2777f6637da02da84c9c1ff92f413ce0f0995084, 59eb22641f0c526dd064390b11cff99ae87c2858
Exploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Linux kernel to 2777f6637da02da84c9c1ff92f413ce0f0995084 or 59eb22641f0c526dd064390b11cff99ae87c2858.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Debiandebian/linuxpkg:deb/debian/linuxOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: spi: imx: fix slab corruption from undersized DMA bounce buffers Since commit faa8e404ad8e ("spi: imx: support dynamic burst length for ECSPI DMA mode"), the driver allocates its private DMA TX/RX buffers with kzalloc(dma_len), where dma_len is only rounded up to 4 bytes, but maps, syncs and unmaps them with DMA_CACHE_ALIGNED_LEN(dma_len), i.e. rounded up to the cache line size. As a result, the DMA API operates on memory beyond the end of the allocation. This was observed on a custom i.MX8MP platform with an mcp251xfd CAN controller under heavy RPMSG load, as a series of refcount_t warnings triggered from rpmsg_recv_done() in virtio_rpmsg_bus: refcount_t: addition on 0; use-after-free. refcount_t: underflow; use-after-free. refcount_t: saturated; leaking memory. Leading finally to an "Unable to handle kernel paging request" oops. Reproducing this problem took between 30 minutes and roughly 30 hours under the same workload. Hardware watchpoints on the refcount of a struct rpmsg_endpoint showed it was overwritten from 2 to 1 by __pi_memcpy_generic() in the irq/155-spi2.0 thread. Additionally it was found that a "normal" rpmsg_recv_done() took 11µs +/-2µs from its kref_get to kref_put. In the error case the same sequence took about 215µs +/-10µs. Based on this, an LLM was used to identify the size mismatch fixed here. Allocate the buffers with DMA_CACHE_ALIGNED_LEN(dma_len) so they cover the full mapped length, and use the same length for dma_sync_single_for_cpu() to stay consistent with map and unmap. With this patch applied, the same workload ran for more than 200 hours without the problem reproducing.