# CVE-2026-89682: linux: In the Linux kernel, the following vulnerability has been resolved: nfsd: fix fcache_disposal UAF by inlining dispos... CVE-2026-89682 is fixed in 20 products on 1 platform, first by DEBIAN-CVE-2026-89682, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-89682 - Priority: High - CVSS: 8.1 (high) - EPSS: 0.0053 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 11, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net nfsd_file_dispose_list_delayed() defers fput() to nfsd service threads via a per-net freeme queue, preventing the shrinker and GC worker from bearing the cost of closing files (see ffb402596147). However, the queue lives in a separately-allocated struct nfsd_fcache_disposal that is freed by nfsd_free_fcache_disposal_net() during per-net teardown. The global shrinker, laundrette, and fsnotify callbacks can still be inside nfsd_file_dispose_list_delayed() dereferencing that pointer, causing a use-after-free. Inline the spinlock and freeme list directly into struct nfsd_net (as fcache_dispose_lock and fcache_dispose_list), eliminating the separately allocated struct nfsd_fcache_disposal entirely. These fields now have the same lifetime as the net namespace itself, so there is no dangling pointer to chase. nfsd_file_cache_start_net() now just initializes the inline fields and cannot fail due to allocation. nfsd_file_cache_shutdown_net() drains the inline list directly instead of freeing a separate struct. The alloc/free helpers are removed. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel-livepatch-6.18.51-120.162 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-89682](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89682.md) | Sep 23, 2026 | | Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89682](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89682.md) | Sep 23, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.51-120.162.amzn2023 | [ALAS2023-2026-3187](https://patchblox.com/security/data/fix/linux/alas2023-2026-3187.md) | Nov 7, 2026 | --- Data as of 2026-11-08T00:53:09Z UTC. 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