# CVE-2026-80810: linux: In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: fix folio size overflow in io_vec... CVE-2026-80810 is fixed in 20 products on 1 platform, first by DEBIAN-CVE-2026-80810, released September 5, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-80810 - Priority: High - CVSS: n/a (important) - EPSS: 0.0021 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 4, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: fix folio size overflow in io_vec_fill_bvec() io_vec_fill_bvec() computes the folio size with a plain int 1: unsigned long folio_size = 1 << imu->folio_shift; imu->folio_shift is unsigned int and comes from folio_shift() of the folio backing the registered buffer, so it can be 32 or more on a 64 bit kernel. Shifting int 1 that far is undefined, and on x86 and arm64 the count is taken modulo 32, so a shift of 34 yields 4 rather than 16G. Every other folio_shift shift in this file already uses 1UL. The result is that the segment estimate and the fill loop disagree. io_estimate_bvec_size() sizes the bvec array with the real shift: max_segs += (iov[i].iov_len >> shift) + 2; so a 1M iovec on a 16G folio is charged 2 segments, while io_vec_fill_bvec() then walks the same iovec in folio_size chunks of 4 bytes and writes res_bvec[bvec_idx] a quarter of a million times, past the end of the array it was given. src_bvec is advanced once per iteration as well, so imu->bvec is read past its end at the same time. validate_fixed_range() only checks that the range is inside the registered buffer and does not bound the segment count. Reaching it needs a folio with a shift of at least 32, which means a gigantic hugetlb page: 16G on arm64 with 64K pages, where CONT_PMD_SHIFT is 34 and hugetlb_add_hstate(CONT_PMD_SHIFT - PAGE_SHIFT) registers that size, and likewise on powerpc. x86_64 tops out at 1G, so a shift of 30, which still fits in int and is unaffected. Use 1UL, as the rest of the file does. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel-livepatch-6.18.48-107.148 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | linux Debian 14 | 7.1.12-1 | [DEBIAN-CVE-2026-80810](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80810.md) | Sep 5, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.48-107.148.amzn2023 | [ALAS2023-2026-3139](https://patchblox.com/security/data/fix/linux/alas2023-2026-3139.md) | Sep 28, 2026 | --- Data as of 2026-11-08T19:12:23Z UTC. 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