# CVE-2026-68174: linux: In the Linux kernel, the following vulnerability has been resolved: tracing: Fix union collision of module and refcn... CVE-2026-68174 is fixed in 20 products on 1 platform, first by DEBIAN-CVE-2026-68174, released August 11, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-68174 - Priority: High - CVSS: n/a (important) - EPSS: 0.0020 - 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: tracing: Fix union collision of module and refcnt for dynamic events In 'struct trace_event_call', the 'module' pointer and the 'refcnt' atomic variable share the same memory space in a union. For dynamic events, the union member is 'refcnt', which acts as an active reference counter. When a dynamic event (such as kprobe, uprobe, fprobe, eprobe, or wprobe) has a non-zero reference count (e.g. due to active event triggers or perf attachments), its 'call->module' evaluates to a small non-zero integer instead of NULL. When filtering or setting events for a specific module (e.g., writing ':mod:' to 'set_event'), the code in '__ftrace_set_clr_event_nolock()' and 'update_event_fields()' reads 'call->module' directly without checking whether the event is dynamic. This causes the kernel to treat the small integer (refcnt) as a 'struct module' pointer, leading to a NULL/invalid pointer dereference (Oops) when dereferencing the module name. Fix this by ensuring that the 'TRACE_EVENT_FL_DYNAMIC' flag is checked before treating 'call->module' as a valid pointer in these code paths. ## 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 14 | 7.1.6-1 | [DEBIAN-CVE-2026-68174](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68174.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 2026-11-08T13:06:02Z UTC. 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