CVE-2026-89962
Vulnérabilité non évaluée dans Linux (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.
Gravité et risque d'exploitation
CVE-2026-89962 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.21 %, ce qui la place devant 10.3 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions 6.18.51, <9ef63622e6cee588ea4b763a6afc87065254b36a, <=*, <=6.12.*, <da88a2a2119e4fd0e8919a7a2448682f574e1545, <c4cb547f26d9b73b489c5278d0c8db837c5a174f, <=7.2.*, <=6.18.*, 7.2.5, 180adfc532a83c1d74146449f7385f767d4b8059, 5.9, 0, <fa40f9dbdd4af53e7445d9135b5b207eb8adf372, <5.9, 6.12.110, 7.3) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.