CVE-2026-98288 net: stmmac: fix TSO header length truncation
A remote attacker can cause a denial of service in the Linux kernel stmmac driver by sending crafted TCP packets with large IPv6 headers, triggering an integer overflow.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98288?
CVE-2026-98288 is a vulnerability in Linux, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-98288?
How do I fix CVE-2026-98288?
Apply the vendor's patch.
Is CVE-2026-98288 being exploited?
There is no known exploitation of CVE-2026-98288 in the wild and no public exploit code.
Sources
Also known as AZL-106452, BELL-CVE-2026-98288, DEBIAN-CVE-2026-98288, GHSA-gg98-59cc-cfq6, UBUNTU-CVE-2026-98288.