CVE-2026-72157

Technical Description

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 fi

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References