CVE-2026-89962

/// Technical description

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

powerpc/kexec_file: Prevent kexec range truncation

Sashiko AI review pointed out the following issue.

The __merge_memory_ranges() function incorrectly handles overlapping

memory ranges when merging them. Although sort_memory_ranges() sorts all

ranges by their start address in ascending order beforehand, the merge

logic remains defective in two ways:

1. It compares the current range's start against the previous element (i-1)

instead of the running target index (idx)

2. It unconditionally overwrites 'ranges[idx].end' with 'ranges[i].end'.

This logic flaw leads to critical memory truncation when a larger memory

range completely subsumes subsequent smaller ranges.

For example, consider a sorted input array with three ranges:

Range A (idx=0): [0x1000 - 0x9000]

Range B (i=1): [0x2000 - 0x5000] (completely inside Range A)

Range C (i=2): [0x6000 - 0x8000] (completely inside Range A)

1. When i=1 (Range B):

/// 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