CVE-2026-89961 Affecting linux-6.12 package, versions <6.12.111-1~deb12u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIAN12-LINUX612-20506651
- published5 Oct 2026
- disclosed16 Sept 2026
Introduced: 16 Sep 2026
NewCVE-2026-89961 (opens in a new tab)How to fix?
Upgrade Debian:12 linux-6.12 to version 6.12.111-1~deb12u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Debian.
See How to fix? for Debian:12 relevant fixed versions and status.
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.
References
- https://security-tracker.debian.org/tracker/CVE-2026-89961
- 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