CVE-2026-31616
概要

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

usb: gadget: f_phonet: fix skb frags[] overflow in pn_rx_complete()

A broken/bored/mean USB host can overflow the skb_shared_info->frags[]
array on a Linux gadget exposing a Phonet function by sending an
unbounded sequence of full-page OUT transfers.

pn_rx_complete() finalizes the skb only when req->actual < req->length,
where req->length is set to PAGE_SIZE by the gadget. If the host always
sends exactly PAGE_SIZE bytes per transfer, fp->rx.skb will never be
reset and each completion will add another fragment via
skb_add_rx_frag(). Once nr_frags exceeds MAX_SKB_FRAGS (default 17),
subsequent frag stores overwrite memory adjacent to the shinfo on the
heap.

Drop the skb and account a length error when the frag limit is reached,
matching the fix applied in t7xx by commit f0813bcd2d9d ("net: wwan:
t7xx: fix potential skb->frags overflow in RX path").

公表日 2026年4月25日0:16
登録日 2026年4月25日4:07
最終更新日 2026年4月25日2:51
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