Use of Uninitialized Variable in Linux kernel - CVE-2026-98438
Published: October 22, 2026
Vulnerability identifier: #VU156736
CSH Severity: Medium
CVSS v4: 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]
CVE-ID: CVE-2026-98438
CWE-ID: CWE-457
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Linux kernel
How to mitigate CVE-2026-98438
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3