# CVE-2026-98858: io_uring: fix task_work add use-after-free with SQPOLL CVE-2026-98858 is fixed in 39 products on 1 platform, first by DEBIAN-CVE-2026-98858, released October 19, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-98858 - 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-2026-98858 ## Description In the Linux kernel, the following vulnerability has been resolved: io_uring: fix task_work add use-after-free with SQPOLL For SQPOLL, the sqpoll thread runs task_work off its own list and doesn't need to be told about it, so it can pop and complete a request as soon as mpscq_push() has published it. If that was the last request holding the ring alive, io_ring_exit_work() then frees the ctx, stops the thread, and with it the tctx, while io_req_normal_work_add() is still looking at both after the push: BUG: KASAN: slab-use-after-free in io_req_normal_work_add+0x439/0x510 Read of size 4 at addr ff11000000ca0000 by task repro/55 (...) BUG: KASAN: slab-use-after-free in queue_work_on+0x25/0x70 Write of size 8 at addr ff11000000c3bd00 by task repro/55 Hold an RCU read lock across the add, like io_req_local_work_add() already does, and have io_ring_exit_work() wait for a grace period for SQPOLL rings as well before freeing the ctx. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.12 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | bpftool6.18 amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel-livepatch-6.12.113-138.209 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel-livepatch-6.18.56-125.164 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.12 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-devel amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-headers amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-tools amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.113-1 | [DEBIAN-CVE-2026-98858](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98858.md) | Oct 19, 2026 | | Linux | linux Debian 14 | 7.2.10-1 | [DEBIAN-CVE-2026-98858](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98858.md) | Oct 19, 2026 | | Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.113-1~deb12u1 | [DEBIAN-CVE-2026-98858](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98858.md) | Oct 19, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | perf6.12 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | python3-perf6.12 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.56-125.164.amzn2023 | [ALAS2023-2026-3251](https://patchblox.com/security/data/fix/linux/alas2023-2026-3251.md) | Nov 7, 2026 | --- Data as of 2026-11-09T13:31:49Z UTC. 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