Out-of-bounds write in Linux kernel - CVE-2026-98403
Published: October 15, 2026
Vulnerability identifier: #VU155910
CSH Severity: Low
CVSS v4: 0 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-98403
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to corrupt memory.
The vulnerability exists due to an out-of-bounds write in append_ipl_block_parm() in arch/s390/boot/ipl_parm.c when appending an IPL parameter to a command line that occupies all but the terminating byte of COMMAND_LINE_SIZE. A local user can supply an IPL parameter that causes the conversion helpers to write beyond the early_command_line buffer to corrupt memory.
Affected software
Linux kernel
Debian Linux
linux (Debian package)
Debian Linux
linux (Debian package)
How to mitigate CVE-2026-98403
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
linux (Debian package) - update to 6.12.113-1
linux (Debian package) - update to 6.12.113-1