{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99238","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-25T10:25:14.403Z","datePublished":"2026-11-02T16:06:42.810Z","dateUpdated":"2026-11-03T19:13:05.949Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-11-03T19:13:05.949Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Hold trace_types_lock when updating modules in persistent instances\n\ntrace_module_record() walks ftrace_trace_arrays from the module notifier\nwithout trace_types_lock. A concurrent rmdir of an instance removes it\nfrom the list and frees it under that lock, so a module load or unload\ncan walk into a freed trace_array."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - trace_module_record() is reached only from trace_module_notify() on MODULE_STATE_COMING/GOING via load_module()->prepare_coming_module() or delete_module(), i.e. local finit_module/init_module/delete_module or __sock_create()'s request_module(\"net-pf-%d\"). The concurrent free is rmdir(2) on tracefs instances (tracefs_syscall_rmdir()->instance_rmdir()). No protocol message carries the list pointer.\nAC:L - The attacker mkdir()s an instance, then concurrently rmdir()s it so __remove_instance() list_del()+kfree()s the trace_array while another thread loads or unloads a module and trace_module_record() walks ftrace_trace_arrays unlocked. They drive both sides and can retry; a boot/persistent instance is unnecessary because the walk visits every trace_array before checking TRACE_ARRAY_FL_BOOT.\nPR:L - instance_mkdir()/instance_rmdir() (via tracefs_syscall_rmdir) check only VFS DAC on the 0750 instances directory and LOCKDOWN_TRACEFS, not capable(). tracefs_parse_param() uid=/gid= makes a non-root owner of that directory. The COMING notifier also runs after __sock_create()'s request_module(\"net-pf-%d\"), which is not gated by CAP_SYS_MODULE.\nUI:N - The attacker mkdir/rmdir their own /sys/kernel/tracing/instances/<name> and starts the module load or unload (socket() autoload, finit_module, or delete_module) on their own threads. No other user must mount media, open a file, or confirm the action.\nS:U - __remove_instance() kfree()s a host-kernel struct trace_array that trace_module_record() still walks on ftrace_trace_arrays. The resulting heap corruption stays in the tracing subsystem on that host and does not cross a VM, IOMMU, or guest/host boundary.\nC:H - After __remove_instance() kfree()s the kzalloc'd trace_array, trace_module_record() still reads tr->flags and list_for_each_entry follows tr->list.next. Reclaiming that object lets the attacker control those fields and the later tr->scratch/tr->module_delta pointers, which is a use-after-free kernel read.\nI:H - If the reclaimed object's flags include TRACE_ARRAY_FL_BOOT, save_mod() writes mod->name and mod_addr through attacker-controlled tr->scratch; if TRACE_ARRAY_FL_LAST_BOOT is set, make_mod_delta() writes tr->module_delta->delta[]. That use-after-free write is a kernel heap and control-flow primitive.\nA:H - list_for_each_entry on the kfree'd trace_array in trace_module_record(), or save_mod()/make_mod_delta() dereferencing stale tr->scratch, oopses or panics the kernel. The attacker can repeat the rmdir-versus-module-notifier race until that crash hits."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace.c"],"versions":[{"version":"5f3719f697c3fdfae5cd6805f10ac7a04b0f4e43","lessThan":"57408eac99b0d8a005796346d317d31f0ca4e07a","status":"affected","versionType":"git"},{"version":"5f3719f697c3fdfae5cd6805f10ac7a04b0f4e43","lessThan":"dab2bd4d67ad5eaa95019a9511f8d379401b5021","status":"affected","versionType":"git"},{"version":"5f3719f697c3fdfae5cd6805f10ac7a04b0f4e43","lessThan":"244c442f54601a24c86ad90572bf36fc3df41c5e","status":"affected","versionType":"git"},{"version":"5f3719f697c3fdfae5cd6805f10ac7a04b0f4e43","lessThan":"66877a312ae3c2c3d849e82e882f642ffd4ec3e2","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace.c"],"versions":[{"version":"6.15","status":"affected"},{"version":"0","lessThan":"6.15","status":"unaffected","versionType":"semver"},{"version":"6.18.60","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.14","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3.1","lessThanOrEqual":"7.3.*","status":"unaffected","versionType":"semver"},{"version":"7.4-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.18.60"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.2.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.3.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.4-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/57408eac99b0d8a005796346d317d31f0ca4e07a"},{"url":"https://git.kernel.org/stable/c/dab2bd4d67ad5eaa95019a9511f8d379401b5021"},{"url":"https://git.kernel.org/stable/c/244c442f54601a24c86ad90572bf36fc3df41c5e"},{"url":"https://git.kernel.org/stable/c/66877a312ae3c2c3d849e82e882f642ffd4ec3e2"}],"title":"tracing: Hold trace_types_lock when updating modules in persistent instances","x_generator":{"engine":"bippy-1.2.0"}}}}