# CVE-2026-43067: linux: In the Linux kernel, the following vulnerability has been resolved: ext4: handle wraparound when searching for block... CVE-2026-43067 is fixed in 41 products on 1 platform, first by ALAS2023-2026-1646, released May 11, 2026. It is not reported as exploited. Patch Radar priority: Urgent. - Web page: https://patchblox.com/security/cve/CVE-2026-43067 - Priority: Urgent - CVSS: 9.8 (critical) - EPSS: 0.0050 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: May 5, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: ext4: handle wraparound when searching for blocks for indirect mapped blocks Commit 4865c768b563 ("ext4: always allocate blocks only from groups inode can use") restricts what blocks will be allocated for indirect block based files to block numbers that fit within 32-bit block numbers. However, when using a review bot running on the latest Gemini LLM to check this commit when backporting into an LTS based kernel, it raised this concern: If ac->ac_g_ex.fe_group is >= ngroups (for instance, if the goal group was populated via stream allocation from s_mb_last_groups), then start will be >= ngroups. Does this allow allocating blocks beyond the 32-bit limit for indirect block mapped files? The commit message mentions that ext4_mb_scan_groups_linear() takes care to not select unsupported groups. However, its loop uses group = *start, and the very first iteration will call ext4_mb_scan_group() with this unsupported group because next_linear_group() is only called at the end of the iteration. After reviewing the code paths involved and considering the LLM review, I determined that this can happen when there is a file system where some files/directories are extent-mapped and others are indirect-block mapped. To address this, add a safety clamp in ext4_mb_scan_groups(). ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.12 amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | bpftool6.18 amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel-livepatch-6.12.80-105.147 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel-livepatch-6.18.25-52.107 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.12 amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-devel amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-headers amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-libbpf amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-libbpf-debuginfo amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-libbpf-devel amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-libbpf-static amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-tools amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | linux Debian 14 | 6.19.11-1 | [DEBIAN-CVE-2026-43067](https://patchblox.com/security/data/fix/linux/debian-cve-2026-43067.md) | May 15, 2026 | | Linux | perf6.12 amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | python3-perf6.12 amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.80-105.147.amzn2023 | [ALAS2023-2026-1646](https://patchblox.com/security/data/fix/linux/alas2023-2026-1646.md) | May 11, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.25-52.107.amzn2023 | [ALAS2023-2026-1746](https://patchblox.com/security/data/fix/linux/alas2023-2026-1746.md) | May 25, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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