In the Linux kernel, the following vulnerability has been resolved:

hv_netvsc: use kmap_local_page in netvsc_copy_to_send_buf

netvsc_copy_to_send_buf() copies page buffer entries into the VMBus
send buffer using phys_to_virt() on the entry PFN. Entries for the
RNDIS header and the skb linear data come from kmalloc'd memory and
are always in the kernel direct map, but entries for skb fragments
reference page cache or user pages, which on 32-bit x86 with
CONFIG_HIGHMEM=y can live above the LOWMEM boundary. For such a page
phys_to_virt() returns an address outside the direct map and the
subsequent memcpy() faults on the transmit softirq path, which is
fatal.

Map the pages with kmap_local_page() instead, handling two properties
of the page buffer entries:

 - pb[i].pfn is a Hyper-V PFN at HV_HYP_PAGE_SIZE (4K) granularity,
   not a native PFN. Reconstruct the physical address first and derive
   the native page from it, so the mapping stays correct where
   PAGE_SIZE > HV_HYP_PAGE_SIZE (e.g. arm64 with 64K pages).

 - Since commit 41a6328b2c55 ("hv_netvsc: Preserve contiguous PFN
   grouping in the page buffer array"), an entry describes a full
   physically contiguous fragment and pb[i].len can exceed PAGE_SIZE,
   while kmap_local_page() maps a single page. Copy page by page,
   splitting at native page boundaries.

The copy path only handles packets smaller than the send section size
(6144 bytes by default); larger packets take the cp_partial path where
only the RNDIS header is copied. So entries here are bounded by the
section size and a copy is split at most once on 4K-page systems. On
!CONFIG_HIGHMEM configs kmap_local_page() folds to page_address() and
no mapping work is added.

https://git.kernel.org/stable/c/004e9ecfe6c5384f9e0b2f6f6389d42ec22789af

https://git.kernel.org/stable/c/09b8a7aa5a341bb345dc492aac139525efa13515

https://git.kernel.org/stable/c/0b38870d81ab3a04c1ab0598d9d3285f5d9d0584

https://git.kernel.org/stable/c/16514afeb7d3d121072ba9a0b640d6c1c5507db0

https://git.kernel.org/stable/c/695c59cf7bf707e6ff8cea01916ee50e86616933

https://git.kernel.org/stable/c/918c0c988239aa5ab96b254e504d191af6191061

https://git.kernel.org/stable/c/a82d4251918f37d9c5aab7b365157669fb885ec3

https://git.kernel.org/stable/c/fe7221b4346418d27ec2daccfc09df6692b76f0b

[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","programFiles":["drivers/net/hyperv/netvsc.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e","lessThan":"16514afeb7d3d121072ba9a0b640d6c1c5507db0","versionType":"git","status":"affected"},{"version":"c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e","lessThan":"a82d4251918f37d9c5aab7b365157669fb885ec3","versionType":"git","status":"affected"},{"version":"c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e","lessThan":"695c59cf7bf707e6ff8cea01916ee50e86616933","versionType":"git","status":"affected"},{"version":"c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e","lessThan":"09b8a7aa5a341bb345dc492aac139525efa13515","versionType":"git","status":"affected"},{"version":"c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e","lessThan":"918c0c988239aa5ab96b254e504d191af6191061","versionType":"git","status":"affected"},{"version":"c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e","lessThan":"0b38870d81ab3a04c1ab0598d9d3285f5d9d0584","versionType":"git","status":"affected"},{"version":"c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e","lessThan":"fe7221b4346418d27ec2daccfc09df6692b76f0b","versionType":"git","status":"affected"},{"version":"c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e","lessThan":"004e9ecfe6c5384f9e0b2f6f6389d42ec22789af","versionType":"git","status":"affected"}]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","programFiles":["drivers/net/hyperv/netvsc.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","versions":[{"version":"3.16","status":"affected"},{"version":"0","lessThan":"3.16","versionType":"semver","status":"unaffected"},{"version":"5.10.259","lessThanOrEqual":"5.10.*","versionType":"semver","status":"unaffected"},{"version":"5.15.210","lessThanOrEqual":"5.15.*","versionType":"semver","status":"unaffected"},{"version":"6.1.176","lessThanOrEqual":"6.1.*","versionType":"semver","status":"unaffected"},{"version":"6.6.143","lessThanOrEqual":"6.6.*","versionType":"semver","status":"unaffected"},{"version":"6.12.94","lessThanOrEqual":"6.12.*","versionType":"semver","status":"unaffected"},{"version":"6.18.36","lessThanOrEqual":"6.18.*","versionType":"semver","status":"unaffected"},{"version":"7.0.13","lessThanOrEqual":"7.0.*","versionType":"semver","status":"unaffected"},{"version":"7.1","lessThanOrEqual":"*","versionType":"original_commit_for_fix","status":"unaffected"}]}]