# CVE-2026-68421: linux: In the Linux kernel, the following vulnerability has been resolved: sched_ext: Don't warn on core-sched forced idle... CVE-2026-68421 is fixed in 20 products on 1 platform, first by DEBIAN-CVE-2026-68421, released August 11, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-68421 - Priority: High - CVSS: n/a (important) - EPSS: 0.0019 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Aug 10, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx() put_prev_task_scx() warns when a runnable task drops to a lower sched_class without SCX_OPS_ENQ_LAST, on the assumption that balance_one() would have kept it running. Core scheduling breaks that: a forced-idle SMT sibling reschedules through the core_pick fast path in pick_next_task(), which skips pick_task_scx() and thus balance_one(), so a runnable task can drop to idle with ENQ_LAST unset. Gate the warning on sched_cpu_cookie_match(): a cookie mismatch means core scheduling forced the idle, while a match (or core scheduling off) still catches a genuine missing-ENQ_LAST drop. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel-livepatch-6.18.44-99.149 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-68421](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68421.md) | Aug 11, 2026 | | Linux | linux Debian 14 | 7.1.6-1 | [DEBIAN-CVE-2026-68421](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68421.md) | Aug 11, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.44-99.149.amzn2023 | [ALAS2023-2026-2106](https://patchblox.com/security/data/fix/linux/alas2023-2026-2106.md) | Aug 31, 2026 | --- Data as of 2026-11-09T07:25:28Z UTC. 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