SB2026102208 - Use of Uninitialized Variable in Linux kernel mptcp

Description

This security bulletin contains information about 1 vulnerability.

1) Use of Uninitialized Variable (CVE-ID: CVE-2026-98438)

CWE-ID: CWE-457 - Use of Uninitialized Variable

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to potentially disrupt MPTCP communication.

The vulnerability exists due to use of an uninitialized checksum value in the Linux kernel's mptcp_write_data_fin() function when sending a DATA_FIN without accompanying data and checksumming has been negotiated. A remote attacker can interact with an affected MPTCP connection to potentially cause incorrect outgoing checksum computation and disrupt communication.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/9a682067dd7b9dce6b94a0a05661dcc921446402
• https://git.kernel.org/stable/c/b110f1dd6cb6a9930503354a01a315e0a821eaa7