# CVE-2025-39961: iommu/amd/pgtbl: Fix possible race while increase page table level CVE-2025-39961 is fixed in 53 products on 1 platform, first by DEBIAN-CVE-2025-39961, released October 9, 2025. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2025-39961 - Priority: Routine - CVSS: 5.8 (Moderate) - EPSS: 0.0012 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Oct 9, 2025 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39961 ## Description In the Linux kernel, the following vulnerability has been resolved: iommu/amd/pgtbl: Fix possible race while increase page table level The AMD IOMMU host page table implementation supports dynamic page table levels (up to 6 levels), starting with a 3-level configuration that expands based on IOVA address. The kernel maintains a root pointer and current page table level to enable proper page table walks in alloc_pte()/fetch_pte() operations. The IOMMU IOVA allocator initially starts with 32-bit address and onces its exhuasted it switches to 64-bit address (max address is determined based on IOMMU and device DMA capability). To support larger IOVA, AMD IOMMU driver increases page table level. But in unmap path (iommu_v1_unmap_pages()), fetch_pte() reads pgtable->[root/mode] without lock. So its possible that in exteme corner case, when increase_address_space() is updating pgtable->[root/mode], fetch_pte() reads wrong page table level (pgtable->mode). It does compare the value with level encoded in page table and returns NULL. This will result is iommu_unmap ops to fail and upper layer may retry/log WARN_ON. CPU 0 CPU 1 ------ ------ map pages unmap pages alloc_pte() -> increase_address_space() iommu_v1_unmap_pages() -> fetch_pte() pgtable->root = pte (new root value) READ pgtable->[mode/root] Reads new root, old mode Updates mode (pgtable->mode += 1) Since Page table level updates are infrequent and already synchronized with a spinlock, implement seqcount to enable lock-free read operations on the read path. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | bpftool-debuginfo amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | bpftool6.12 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-debuginfo amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.8.1.160000.2.5 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.8.1.160000.2.5 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-devel amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-headers amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-livepatch-6.1.175-219.357 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-livepatch-6.12.53-69.119 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel-modules-extra amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-modules-extra-common amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-tools amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-tools-debuginfo amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-tools-devel amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel6.12 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-devel amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-headers amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-libbpf amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-libbpf-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-libbpf-devel amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-libbpf-static amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-tools amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.12.57-1 | [DEBIAN-CVE-2025-39961](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39961.md) | Oct 9, 2025 | | Linux | linux Debian 14 | 6.16.9-1 | [DEBIAN-CVE-2025-39961](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39961.md) | Oct 9, 2025 | | Linux | perf amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | perf-debuginfo amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | perf6.12 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | python3-perf amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | python3-perf-debuginfo amzn 2023 | 1:6.1.175-219.357.amzn2023 | [ALAS2023-2026-1882](https://patchblox.com/security/data/fix/linux/alas2023-2026-1882.md) | Jun 22, 2026 | | Linux | python3-perf6.12 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | | Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 | --- Data as of 2026-11-09T19:38:12Z UTC. 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