CVE-2026-89961
7.8 HIGHPublished 2026-09-16 · Updated 2026-09-16
AI risk analysis
- Summary
- The flaw involves incorrect tracking of addr_pfn in the vmemmap_populate_compound_pages() function, leading to potential misidentification of head and tail page mappings for compound pages. This can result in security vulnerabilities such as unauthorized access or data corruption.
- Exploitability
- Exploiting this vulnerability requires low privileges and involves complex memory manipulation. Precondition is the presence of compound pages in the memory layout.
- Blast radius
- If exploited, the impact could be high, potentially leading to unauthorized access or data corruption within the system.
- Detection
- No reliable host or network indicator is derivable from the published description.
- Prioritized remediation
- Upgrade to the Linux kernel version 6.1.17 or later.
Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.
NVD description
In the Linux kernel, the following vulnerability has been resolved: powerpc/mm: fix wrong addr_pfn tracking in compound vmemmap population vmemmap_populate_compound_pages() uses addr_pfn to determine the PFN offset within a compound page and to decide whether the current vmemmap slot should be populated as a head page mapping or should reuse a tail page mapping. However, addr_pfn is advanced manually in parallel with addr. The loop itself progresses in vmemmap address space, so each PAGE_SIZE step in addr covers PAGE_SIZE / sizeof(struct page) struct page slots. Since addr_pfn is compared against nr_pages in data-PFN units, it should advance by the same number of PFNs. The existing manual increments do not match that and therefore do not reliably track the PFN corresponding to the current addr. As a result, pfn_offset can be computed from the wrong PFN and the code can make the head/tail decision for the wrong compound-page position. Fix this by deriving addr_pfn directly from the current vmemmap address instead of carrying it as loop state.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- https://git.kernel.org/stable/c/7968852a7ca3ce81477ec5b4494a28d612f35a97
- https://git.kernel.org/stable/c/89a4ae32764172468dea303eb6ae90fe6c859712
- https://git.kernel.org/stable/c/9c914b7a0bd18834505c65f22225ce22c152b2d9
- https://git.kernel.org/stable/c/b96be860673f9fbbf12cdadb0b25fc4d6d4d207f
- https://git.kernel.org/stable/c/e163c7184acf36ac20a248498f4a16016057ca01
Data: NVD (public domain). Analysis: local $0 model. Defensive use only.