CVE-2026-89962
CVE CVE-2026-89962EUVD EUVD-2026-80562Published 2026-09-16T10:32:44.000Z
What the advisory describes
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.
Source: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Linux — Linux 5.9; patch: 6.18.51; patch: 7.3-rc1; 180adfc532a83c1d74146449f7385f767d4b8059 <9ef63622e6cee588ea4b763a6afc87065254b36a; patch: 6.12.110; patch: 7.2.5; 180adfc532a83c1d74146449f7385f767d4b8059 <c4cb547f26d9b73b489c5278d0c8db837c5a174f; patch: 0; 180adfc532a83c1d74146449f7385f767d4b8059 <fa40f9dbdd4af53e7445d9135b5b207eb8adf372; 180adfc532a83c1d74146449f7385f767d4b8059 <da88a2a2119e4fd0e8919a7a2448682f574e1545
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
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- Linux — Linux
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