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CVE-2026-89962 Affecting linux-6.12 package, versions <6.12.111-1~deb12u1

Severity

 Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.21% (10th percentile)

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  • Snyk IDSNYK-DEBIAN12-LINUX612-20506337
  • published5 Oct 2026
  • disclosed16 Sept 2026
Report a new vulnerability Found a mistake?

Introduced: 16 Sep 2026

NewCVE-2026-89962  (opens in a new tab)

How to fix?

Upgrade Debian:12 linux-6.12 to version 6.12.111-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

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): ranges[1].start (0x2000) <= ranges[0].end + 1 (0x9001) is TRUE. The code executes: ranges[0].end = ranges[1].end, which erroneously shrinks Range A's end from 0x9000 down to 0x5000.

  2. When i=2 (Range C): ranges[2].start (0x6000) <= ranges[1].end + 1 (0x5001) is FALSE. The code falls into the else block, creating a broken new range.

As a result, valid memory fragments [0x5001 - 0x5fff] and [0x8001 - 0x9000] are completely lost from the kexec exclude lists, potentially allowing the crash kernel to overwrite active memory, causing data corruption or crashes.

Fix this by ensuring the start of the current range is compared against the end of the active merged range (idx), and use max() to safely prevent the outer boundary from being truncated.