CVE-2026-97906

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

bootconfig: Fix integer overflow in initrd size check

Sashiko reported that in get_boot_config_from_initrd(), a crafted initrd

with a huge bootconfig size (such as 0xFFFFFFFF) can cause the pointer

arithmetic:

data = ((void *)hdr) - size;

to wrap around on 32-bit systems (or when pointer subtraction overflows).

Because data wraps around, the subsequent bounds check:

if ((unsigned long)data < initrd_start)

evaluates to false, bypassing the check. The kernel then calls

xbc_calc_checksum(data, size), which attempts to read 4GB of memory,

hitting unmapped pages and triggering a fatal kernel page fault during

early boot. Furthermore, on 64-bit systems with an initrd > 4.29 GB, an

unbounded 32-bit size can similarly bypass the initrd_start check.

Fix this by:

1. Ensuring the initrd is at least large enough to contain the bootconfig

footer and verifying hdr is within the initrd bounds.

2. Checking that size

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References