# CVE-2026-97533: x86/mm/pat: Acquire init_mm read lock on attribute changes to avoid UAF CVE-2026-97533 is fixed in 33 products on 1 platform, first by DEBIAN-CVE-2026-97533, released October 2, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-97533 - Priority: High - CVSS: n/a (important) - EPSS: 0.0022 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 25, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97533 ## Description In the Linux kernel, the following vulnerability has been resolved: x86/mm/pat: Acquire init_mm read lock on attribute changes to avoid UAF A previous commit protected against races between ptdump and CPA collapse, however one still exists between attribute changes and collapse as reported by Denis V. Lunev (linked). When an attribute change arises, a lockless page table walker obtains a PTE entry, which is later written to via set_pte_atomic(): ... -> change_page_attr_set_clr() -> __change_page_attr_set_clr() -> __change_page_attr() -> _lookup_address_cpa() -> lookup_address_in_pgd_attr() -> [ lockless page table walker ] -> set_pte_atomic() There is nothing preventing a concurrent CPA collapse which can free the PTE that was retrieved here, resulting in a use-after-free. With the mmap write lock taken on init_mm over CPA collapse, resolve this race by acquiring an mmap read lock on init_mm over __change_page_attr_set_clr(). This locks across the whole operation over which the walk and the PTE entry write occurs, solving the race. It is safe to do this here, as no spinlocks are held upon entry to __change_page_attr_set_clr(). However, the lock must not be held over an allocation, as allocation can trigger reclaim and shrinkers may call into CPA recursively, making deadlocks possible (init_mm -> ... -> fs_reclaim -> init_mm). A page table is allocated when a huge page needs to be split: -> change_page_attr_set_clr() -> __change_page_attr_set_clr() -> __change_page_attr() -> split_large_page() [ pagetable_alloc() ] -> __split_large_page() Avoid deadlocks by dropping the mmap lock across pagetable_alloc() in split_large_page() and track whether this is needed by adding a new 'init_mm_read_locked' flag to struct cpa_data. This is safe as __split_large_page() (called with locks re-established) revalidates that the page table entry is the same as it was prior to the locks being dropped and __change_page_attr() repeats the entire page table walk whenever a split occurs, so concurrent split and collapse are accounted for. Concurrent ptdump is also safe as the lock is only dropped over page table allocation during which time the page table has not yet been modified. The CPA_COLLAPSE flag is only set by set_memory_rox(), which exclusively operates upon vmalloc ranges, and on x86 only within the module mapping space. This is important, because some callers directly invoke __change_page_attr_set_clr(), bypassing this lock. However, none of these operate within the module mapping space. * cpa_process_alias() - a recursive helper called by __change_page_attr_set_clr(). * __set_memory_enc_pgtable() - operates on the direct mapping and (via __vmbus_establish_gpadl()) the vmalloc mapping space. * __set_pages_[n]p() - called by set_direct_map_[invalid, default, valid]_noflush(), __kernel_map_pages() - operates on the direct map. * kernel_[un]map_pages_in_pgd() - operates on EFI ranges. This work is based upon Denis V. Lunev's excellent analysis of the bug with gratitude. [ dhansen: move to imperative voice in changelog ] ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.40.1.160000.2.29 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.40.1.160000.2.29 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-livepatch-6.18.54-121.166 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | linux Debian 14 | 7.2.7-1 | [DEBIAN-CVE-2026-97533](https://patchblox.com/security/data/fix/linux/debian-cve-2026-97533.md) | Oct 2, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.54-121.166.amzn2023 | [ALAS2023-2026-3192](https://patchblox.com/security/data/fix/linux/alas2023-2026-3192.md) | Nov 7, 2026 | --- Data as of 2026-11-08T00:53:09Z UTC. 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