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 framecount frames therefore ends up with framecount - 1 fragments. tbnetcheckframe() only bounds the peer supplied framecount to TBNETRINGSIZE / 4 (64), which is far above MAXSKBFRAGS (17 by default). A peer that sends a packet of 19 or more small frames pushes nrfrags past MAXSKBFRAGS, so skbaddrxfrag() writes past skbshinfo()->frags[] and corrupts memory after the shared info.

Tighten the start of packet bound to MAXSKBFRAGS + 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()").