# CVE-2026-45999: erofs: fix unsigned underflow in z_erofs_lz4_handle_overlap()

CVE-2026-45999 is fixed in 68 products on 1 platform, first by ALAS2023-2026-1753, released May 25, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-45999
- Priority: High
- CVSS: 7.1 (Moderate)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 25, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45999

## Description

In the Linux kernel, the following vulnerability has been resolved:  erofs: fix unsigned underflow in z_erofs_lz4_handle_overlap()  Some crafted images can have illegal (!partial_decoding && m_llen < m_plen) extents, and the LZ4 inplace decompression path can be wrongly hit, but it cannot handle (outpages < inpages) properly: "outpages - inpages" wraps to a large value and the subsequent rq->out[] access reads past the decompressed_pages array.  However, such crafted cases can correctly result in a corruption report in the normal LZ4 non-inplace path.  Let's add an additional check to fix this for backporting.  Reproducible image (base64-encoded gzipped blob):  H4sIAJGR12kCA+3SPUoDQRgG4MkmkkZk8QRbRFIIi9hbpEjrHQI5ghfwCN5BLCzTGtLbBI+g dilSJo1CnIm7GEXFxhT6PDDwfrs73/ywIQD/1ePD4r7Ou6ETsrq4mu7XcWfj++Pb58nJU/9i PNtbjhan04/9GtX4qVYc814WDqt6FaX5s+ZwXXeq52lndT6IuVvlblytLMvh4Gzwaf90nsvz 2DF/21+20T/ldgp5s1jXRaN4t/8izsy/OUB6e/Qa79r+JwAAAAAAAL52vQVuGQAAAP6+my1w ywAAAAAAAADwu14ATsEYtgBQAAA=  $ mount -t erofs -o cache_strategy=disabled foo.erofs /mnt $ dd if=/mnt/data of=/dev/null bs=4096 count=1

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bpftool amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | bpftool-debuginfo amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | bpftool6.12 amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | bpftool6.18 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-64kb sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-azure sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-debuginfo amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-default sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.36.1.160000.2.17 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-default-base sles 16.0 | 6.12.0-160000.36.1.160000.2.17 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-devel amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-docs sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-headers amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-livepatch-6.1.176-220.358 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-livepatch-6.12.88-119.157 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel-livepatch-6.18.30-61.116 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel-modules-extra amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-modules-extra-common amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-source sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-syms sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel-tools amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-tools-debuginfo amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-tools-devel amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.36.1 | [OPENSUSE-SU-2026:21388-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21388-1.md) | Jul 21, 2026 |
| Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.36.1 | [SUSE-SU-2026:22835-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22835-1.md) | Jul 21, 2026 |
| Linux | kernel6.12 amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-devel amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-headers amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-tools amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | kernel6.18 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-devel amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-headers amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-tools amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | linux Debian 12.15 (bookworm) | 6.1.176-1 | [DEBIAN-CVE-2026-45999](https://patchblox.com/security/data/fix/linux/debian-cve-2026-45999.md) | May 27, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.88-1 | [DEBIAN-CVE-2026-45999](https://patchblox.com/security/data/fix/linux/debian-cve-2026-45999.md) | May 27, 2026 |
| Linux | linux Debian 14 | 7.0.4-1 | [DEBIAN-CVE-2026-45999](https://patchblox.com/security/data/fix/linux/debian-cve-2026-45999.md) | May 27, 2026 |
| Linux | perf amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | perf-debuginfo amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | perf6.12 amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | perf6.18 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | python3-perf amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | python3-perf-debuginfo amzn 2023 | 1:6.1.176-220.358.amzn2023 | [ALAS2023-2026-1924](https://patchblox.com/security/data/fix/linux/alas2023-2026-1924.md) | Jul 6, 2026 |
| Linux | python3-perf6.12 amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.88-119.157.amzn2023 | [ALAS2023-2026-1753](https://patchblox.com/security/data/fix/linux/alas2023-2026-1753.md) | May 25, 2026 |
| Linux | python3-perf6.18 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |
| Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 |

---

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