{"id":"AZL-101217","summary":"CVE-2026-89961 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/mm: fix wrong addr_pfn tracking in compound vmemmap population\n\nvmemmap_populate_compound_pages() uses addr_pfn to determine the PFN\noffset within a compound page and to decide whether the current vmemmap\nslot should be populated as a head page mapping or should reuse a tail\npage mapping.\n\nHowever, addr_pfn is advanced manually in parallel with addr.  The loop\nitself progresses in vmemmap address space, so each PAGE_SIZE step in addr\ncovers PAGE_SIZE / sizeof(struct page) struct page slots.  Since addr_pfn\nis compared against nr_pages in data-PFN units, it should advance by the\nsame number of PFNs.  The existing manual increments do not match that and\ntherefore do not reliably track the PFN corresponding to the current addr.\n\nAs a result, pfn_offset can be computed from the wrong PFN and the code\ncan make the head/tail decision for the wrong compound-page position.\n\nFix this by deriving addr_pfn directly from the current vmemmap address\ninstead of carrying it as loop state.","modified":"2026-09-18T05:37:08Z","published":"2026-09-16T11:17:06Z","upstream":["CVE-2026-89961"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89961"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-101217.json"}}],"schema_version":"1.9.0"}