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CVE-2026-53199

hv_netvsc: use kmap_local_page in netvsc_copy_to_send_buf

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e · fixed in 16514afeb7d3d121072ba9a0b640d6c1c5507db0; From c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e · fixed in a82d4251918f37d9c5aab7b365157669fb885ec3; From c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e · fixed in 695c59cf7bf707e6ff8cea01916ee50e86616933; From c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e · fixed in 09b8a7aa5a341bb345dc492aac139525efa13515; From c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e · fixed in 918c0c988239aa5ab96b254e504d191af6191061; From c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e · fixed in 0b38870d81ab3a04c1ab0598d9d3285f5d9d0584; From c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e · fixed in fe7221b4346418d27ec2daccfc09df6692b76f0b; From c25aaf814a63f9d9c4e45416f13d70ef0aa0be2e · fixed in 004e9ecfe6c5384f9e0b2f6f6389d42ec22789af

  • Linux Linux

    3.16

  • KernelLinux

    From 3.16.0 · fixed in 5.10.259; From 5.11.0 · fixed in 5.15.210; From 5.16.0 · fixed in 6.1.176; From 6.2.0 · fixed in 6.6.143; From 6.7.0 · fixed in 6.12.94; From 6.13.0 · fixed in 6.18.36; From 6.19.0 · fixed in 7.0.13

References 8

git.kernel.org