CVE-2026-64124: net: devmem: reject dma-buf bind with non-page-aligned size or SG length

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-19 · updated 2026-08-13

Description

In the Linux kernel, the following vulnerability has been resolved: net: devmem: reject dma-buf bind with non-page-aligned size or SG length net_devmem_bind_dmabuf() trusts dmabuf->size and sg_dma_len() to be PAGE_SIZE multiples without checking: - tx_vec is sized dmabuf->size / PAGE_SIZE, and net_devmem_get_niov_at() only bounds-checks virt_addr < dmabuf->size before indexing tx_vec[virt_addr / PAGE_SIZE]. With size = N*PAGE_SIZE + r (1 <= r < PAGE_SIZE), sendmsg() at iov_base = N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past. - owner->area.num_niovs = len / PAGE_SIZE while gen_pool_add_owner() covers the full byte len, so a non-page-multiple non-final sg desyncs num_niovs from the gen_pool region for every later sg, on both RX and TX. dma-buf does not require page-aligned sizes, so the bind path has to enforce what its own indexing assumes. Reject both with -EINVAL. The size check is TX-only (only tx_vec is sized off dmabuf->size); the SG-length check covers both directions.

Affected products

Linux kernel: from 6.16 before 6.18.35; from 6.19 before 7.0.11; 7.1-rc1, 7.1-rc2, 7.1-rc3, 7.1-rc4 — fixed in 6.18.35, 7.0.11

How to fix

Upgrade to a fixed version: Linux kernel 6.18.35, 7.0.11. Check the vendor advisory for mitigations.

References

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