{"id":"CVE-2026-68174","summary":"tracing: Fix union collision of module and refcnt for dynamic events","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix union collision of module and refcnt for dynamic events\n\nIn 'struct trace_event_call', the 'module' pointer and the 'refcnt'\natomic variable share the same memory space in a union. For dynamic\nevents, the union member is 'refcnt', which acts as an active\nreference counter.\n\nWhen a dynamic event (such as kprobe, uprobe, fprobe, eprobe, or\nwprobe) has a non-zero reference count (e.g. due to active event\ntriggers or perf attachments), its 'call-\u003emodule' evaluates to a\nsmall non-zero integer instead of NULL.\n\nWhen filtering or setting events for a specific module (e.g., writing\n':mod:\u003cmodule\u003e' to 'set_event'), the code in\n'__ftrace_set_clr_event_nolock()' and 'update_event_fields()' reads\n'call-\u003emodule' directly without checking whether the event is dynamic.\nThis causes the kernel to treat the small integer (refcnt) as a\n'struct module' pointer, leading to a NULL/invalid pointer dereference\n(Oops) when dereferencing the module name.\n\nFix this by ensuring that the 'TRACE_EVENT_FL_DYNAMIC' flag is checked\nbefore treating 'call-\u003emodule' as a valid pointer in these code paths.","modified":"2026-08-12T04:18:46.413549809Z","published":"2026-08-10T11:59:44.417Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68174.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/43a23dfe0024afd3d2b0232e987d0292919a9b24"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b4eb07bde606c2096b24252be589e735eff6d413"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b6a4575f22925da7e6aa00171e9fc0e5029c0bc9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68174.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68174"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4c86bc531e60900053384867c082675bba82c29f"},{"fixed":"b6a4575f22925da7e6aa00171e9fc0e5029c0bc9"},{"fixed":"43a23dfe0024afd3d2b0232e987d0292919a9b24"},{"fixed":"b4eb07bde606c2096b24252be589e735eff6d413"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-68174.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.14.0"},{"fixed":"6.18.42"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-68174.json"}}],"schema_version":"1.9.0"}