Linux Kernel Command Line Buffer Overflow Vulnerability in s390/boot

CVE-2026-98403

What is CVE-2026-98403?

A buffer overflow vulnerability exists in the s390/boot component of the Linux kernel. This issue arises when a command line fills almost the entire COMMAND_LINE_SIZE, leading to a potential overflow during parameter conversion. Specifically, the function append_ipl_block_parm() may pass an incorrect zero size to the helpers responsible for handling IPL parameters, resulting in overwritten memory locations outside the intended command line buffer. This flaw could allow arbitrary command line parameters to overwrite crucial areas of memory, potentially compromising system stability and security.

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