CVE-2026-98288

net: stmmac: fix TSO header length truncation

Published Oct 6, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-190
Type Values Removed Values Added
Weaknesses CWE-681
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-190
Type Values Removed Values Added
Weaknesses CWE-190
Type Values Removed Values Added
Weaknesses CWE-190
Type Values Removed Values Added
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.
Title net: stmmac: fix TSO header length truncation
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 9:16 AM
Reserved
Sep 25, 2026, 10:25 AM
Status
Received
Published
Oct 6, 2026, 9:18 AM
Modified
Oct 19, 2026, 10:18 AM
Severity
Moderate
Public date
Oct 6, 2026, 12:00 AM