GHSA-52P7-4C9H-JCC7
Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 12:30In 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:
-
It compares the current range's start against the previous element (i-1) instead of the running target index (idx)
-
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)
-
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.
-
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": [],
"aliases": [
"CVE-2026-89962"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-16T11:17:06Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/kexec_file: Prevent kexec range truncation\n\nSashiko AI review pointed out the following issue.\n\nThe __merge_memory_ranges() function incorrectly handles overlapping\nmemory ranges when merging them. Although sort_memory_ranges() sorts all\nranges by their start address in ascending order beforehand, the merge\nlogic remains defective in two ways:\n\n1. It compares the current range\u0027s start against the previous element (i-1)\n instead of the running target index (idx)\n\n2. It unconditionally overwrites \u0027ranges[idx].end\u0027 with \u0027ranges[i].end\u0027.\n\nThis logic flaw leads to critical memory truncation when a larger memory\nrange completely subsumes subsequent smaller ranges.\n\nFor example, consider a sorted input array with three ranges:\n Range A (idx=0): [0x1000 - 0x9000]\n Range B (i=1): [0x2000 - 0x5000] (completely inside Range A)\n Range C (i=2): [0x6000 - 0x8000] (completely inside Range A)\n\n1. When i=1 (Range B):\n ranges[1].start (0x2000) \u003c= ranges[0].end + 1 (0x9001) is TRUE.\n The code executes: ranges[0].end = ranges[1].end, which erroneously\n shrinks Range A\u0027s end from 0x9000 down to 0x5000.\n\n2. When i=2 (Range C):\n ranges[2].start (0x6000) \u003c= ranges[1].end + 1 (0x5001) is FALSE.\n The code falls into the else block, creating a broken new range.\n\nAs a result, valid memory fragments [0x5001 - 0x5fff] and [0x8001 - 0x9000]\nare completely lost from the kexec exclude lists, potentially allowing\nthe crash kernel to overwrite active memory, causing data corruption\nor crashes.\n\nFix this by ensuring the start of the current range is compared against the\nend of the active merged range (idx), and use max() to safely prevent the\nouter boundary from being truncated.",
"id": "GHSA-52p7-4c9h-jcc7",
"modified": "2026-09-16T12:30:43Z",
"published": "2026-09-16T12:30:43Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89962"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9ef63622e6cee588ea4b763a6afc87065254b36a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c4cb547f26d9b73b489c5278d0c8db837c5a174f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/da88a2a2119e4fd0e8919a7a2448682f574e1545"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fa40f9dbdd4af53e7445d9135b5b207eb8adf372"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.