# CVE-2026-53027: fs/ntfs3: fix missing run load for vcn0 in attr_data_get_block_locked() CVE-2026-53027 is fixed in 39 products on 1 platform, first by DEBIAN-CVE-2026-53027, released June 25, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-53027 - Priority: High - CVSS: 7.1 (Important) - EPSS: 0.0012 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 24, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-53027 ## Description In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: fix missing run load for vcn0 in attr_data_get_block_locked() When a compressed or sparse attribute has its clusters frame-aligned, vcn is rounded down to the frame start using cmask, which can result in vcn != vcn0. In this case, vcn and vcn0 may reside in different attribute segments. The code already handles the case where vcn is in a different segment by loading its runs before allocation. However, it fails to load runs for vcn0 when vcn0 resides in a different segment than vcn. This causes run_lookup_entry() to return SPARSE_LCN for vcn0 since its segment was never loaded into the in-memory run list, triggering the WARN_ON(1). Fix this by adding a missing check for vcn0 after the existing vcn segment check. If vcn0 falls outside the current segment range [svcn, evcn1), find and load the attribute segment containing vcn0 before performing the run lookup. The following scenario triggers the bug: attr_data_get_block_locked() vcn = vcn0 & cmask <- vcn != vcn0 after frame alignment load runs for vcn segment <- vcn0 segment not loaded! attr_allocate_clusters() <- allocation succeeds run_lookup_entry(vcn0) <- vcn0 not in run -> SPARSE_LCN WARN_ON(1) <- bug fires here! ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.12 amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | bpftool6.18 amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel-livepatch-6.12.100-125.179 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel-livepatch-6.18.39-79.141 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.12 amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-devel amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-headers amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-tools amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.96-1 | [DEBIAN-CVE-2026-53027](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53027.md) | Jun 25, 2026 | | Linux | linux Debian 14 | 7.0.10-1 | [DEBIAN-CVE-2026-53027](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53027.md) | Jun 25, 2026 | | Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.100-1~deb12u1 | [DEBIAN-CVE-2026-53027](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53027.md) | Jun 25, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | perf6.12 amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | python3-perf6.12 amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.100-125.179.amzn2023 | [ALAS2023-2026-2057](https://patchblox.com/security/data/fix/linux/alas2023-2026-2057.md) | Aug 17, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.39-79.141.amzn2023 | [ALAS2023-2026-2045](https://patchblox.com/security/data/fix/linux/alas2023-2026-2045.md) | Aug 3, 2026 | --- Data as of 2026-11-10T01:44:33Z UTC. 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