CVE-2026-99127
CVE-2026-99127CVE-2026-99127
Description
In the Linux kernel, the following vulnerability has been resolved:
page_pool: keep frag_offset aligned for odd-sized requests
page_pool_alloc_frag_netmem() rounds the requested fragment size with
size = ALIGN(size, dma_get_cache_alignment());
dma_get_cache_alignment() returns 1 unless the architecture defines
ARCH_DMA_MINALIGN, which DMA-coherent architectures such as x86 do not.
There the ALIGN() is a no-op and pool->frag_offset advances by the raw,
unrounded size.
A single caller asking for an odd size then leaves frag_offset misaligned
for every fragment carved out of that page afterwards. The pool is shared,
so the damage is not confined to the caller that caused it.
The per-cpu system_page_pool used by generic XDP hits this.
skb_pp_cow_data() allocates its fragments with the raw packet length:
size = min_t(u32, len, PAGE_SIZE);
truesize = size;
page = page_pool_dev_alloc(pool, &page_off, &truesize);
leaving frag_offset odd for whatever is carved out of that page next
Scoring
| Last modified | 2026-10-28 |