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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-89962

powerpc/kexec_file: Prevent kexec range truncation

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Status
Published
Published
Updated
Assigning organization
Linux

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): 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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 180adfc532a83c1d74146449f7385f767d4b8059 to < ffbdc2a3834a3e47bac7236a71bbc82b45c83832affected
  • 180adfc532a83c1d74146449f7385f767d4b8059 to < 9ef63622e6cee588ea4b763a6afc87065254b36aaffected
  • 180adfc532a83c1d74146449f7385f767d4b8059 to < da88a2a2119e4fd0e8919a7a2448682f574e1545affected
  • 180adfc532a83c1d74146449f7385f767d4b8059 to < c4cb547f26d9b73b489c5278d0c8db837c5a174faffected
  • 180adfc532a83c1d74146449f7385f767d4b8059 to < fa40f9dbdd4af53e7445d9135b5b207eb8adf372affected

Linux Linux

Default version status: affected

  • 5.9affected
  • 0 to < 5.9unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.110 to ≤ 6.12.*unaffected
  • 6.18.51 to ≤ 6.18.*unaffected
  • 7.2.5 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References