# CVE-2026-98788: futex: Fix private hash use-after-free on resize CVE-2026-98788 is fixed in 20 products on 1 platform, first by DEBIAN-CVE-2026-98788, released October 19, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-98788 - Priority: High - CVSS: n/a (important) - EPSS: 0.0016 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Oct 18, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98788 ## Description In the Linux kernel, the following vulnerability has been resolved: futex: Fix private hash use-after-free on resize poll_state_synchronize_rcu(mm->futex.phash.batches) is used by futex_ref_drop() to check that a grace period has passed since the current hash was published. This relies on batches referencing a grace period which started after the hash pointer was assigned. __futex_pivot_hash() sets mmph->batches before it replaces mmph->hash: scoped_guard(rcu) { mmph->batches = get_state_synchronize_rcu(); rcu_assign_pointer(mmph->hash, new); } The scoped_guard(rcu) doesn't stop new grace periods from starting, and if one starts between those two assignments, futex_ref_drop() can move forward while a reader still holds a pointer to the old hash. Fix things by setting mmph->batches after assigning mmph->hash. The scoped_guard(rcu) isn't needed, so let's drop that as well. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel-livepatch-6.18.56-126.188 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | linux Debian 14 | 7.2.10-1 | [DEBIAN-CVE-2026-98788](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98788.md) | Oct 19, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.56-126.188.amzn2023 | [ALAS2023-2026-3390](https://patchblox.com/security/data/fix/linux/alas2023-2026-3390.md) | Nov 10, 2026 | --- Data as of 2026-11-11T13:47:35Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.