CVE-2026-72157

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

net: thunderbolt: Fix frags[] overflow by bounding frame_count

tbnet_poll() assembles a multi-frame ThunderboltIP packet into one skb. The

first frame goes into the skb linear area and every further frame is added as

a page fragment.

skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,

page, hdr_size, frame_size,

TBNET_RX_PAGE_SIZE - hdr_size);

A packet of frame_count frames therefore ends up with frame_count - 1

fragments. tbnet_check_frame() only bounds the peer supplied frame_count to

TBNET_RING_SIZE / 4 (64), which is far above MAX_SKB_FRAGS (17 by default). A

peer that sends a packet of 19 or more small frames pushes nr_frags past

MAX_SKB_FRAGS, so skb_add_rx_frag() writes past skb_shinfo()->frags[] and

corrupts memory after the shared info.

Tighten the start of packet bound to MAX_SKB_FRAGS + 1 so a packet can never

produce more fragments than frags[] can hold. This matches the recent skb

frags overflow fixes in other receive paths, for example f0813bcd2d9d ("net:

wwan: t7xx: fix potential skb->frags overflow in RX path") and 600dc40554dc

("net: usb: cdc-phonet: fix skb frags[] overflow in rx_complete()").