{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99237","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-25T10:25:14.402Z","datePublished":"2026-11-02T16:06:42.386Z","dateUpdated":"2026-11-03T19:13:04.997Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-11-03T19:13:04.997Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Hold trace_types_lock when resetting last boot data from readers\n\nupdate_last_data_if_empty() is called from tracing_open() with O_TRUNC,\ntracing_read_pipe() and tracing_buffers_read() without trace_types_lock.\nTwo readers can both pass the LAST_BOOT test and free module_delta\ntwice, and a module notifier can update module_delta while it is being\nfreed.\n\nTake trace_types_lock in those paths and keep the callers that already\nhold it on an unlocked variant."}],"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 - Reached only via local tracefs on a last-boot instance: tracing_open() with O_TRUNC on instances/<name>/trace, tracing_read_pipe() on trace_pipe, and tracing_buffers_read() on per_cpu/cpuN/trace_pipe_raw all call update_last_data_if_empty() without trace_types_lock. No remote protocol supplies the trigger.\nAC:L - The attacker controls both sides. Two threads can open() the last-boot instance's trace with O_TRUNC, or drain the buffer then race tracing_buffers_read() on two trace_pipe_raw fds; both call update_last_data_if_empty() unlocked so each can pass TRACE_ARRAY_FL_LAST_BOOT and kfree_rcu() the same module_delta. The module-notifier race is not required.\nPR:L - tracing_check_open_get_tr() checks only LOCKDOWN_TRACEFS and tracing_disabled, not capable(). trace is TRACE_MODE_WRITE (0640) and trace_pipe/trace_pipe_raw are TRACE_MODE_READ (0440). tracefs uid=/gid= mounts delegate those inodes to a non-root tracing group on Android/Perfetto and embedded systems that use reserve_mem persistent instances.\nUI:N - The attacker opens, truncates, and reads their own last-boot instance descriptors (tracing_open(O_TRUNC) or tracing_buffers_read()). No other user must mount media, enable tracing, or consume the buffer first.\nS:U - The double-free of tr->module_delta is in the host kernel heap (update_last_data() kfree_rcu() racing make_mod_delta()). It can escalate locally but does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Two update_last_data() callers can both READ_ONCE(tr->module_delta) then kfree_rcu() it, and make_mod_delta() still indexes module_delta->delta[] after the free. That slab use-after-free of the flex-array object is an arbitrary kernel-memory read primitive.\nI:H - The same double kfree_rcu(module_delta) plus make_mod_delta() writing module_delta->delta[i] after the object is freed is a heap use-after-free write. Reclaiming that slab yields an arbitrary kernel write and control-flow hijack, not merely a crash.\nA:H - Double-free of module_delta, or make_mod_delta() using it after WRITE_ONCE(tr->module_delta, NULL), oopses or panics the kernel. The attacker retriggers that crash through the unlocked tracing_open(O_TRUNC) or tracing_buffers_read() paths."}]}],"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":"32dc0042528d385d83bf458e4cf3a49c5110afea","lessThan":"92b69f6db640dadc0851762ee2e12db99f083cad","status":"affected","versionType":"git"},{"version":"32dc0042528d385d83bf458e4cf3a49c5110afea","lessThan":"d6d991afe775ab7fcf89523a2502b7ca3be56ffd","status":"affected","versionType":"git"},{"version":"32dc0042528d385d83bf458e4cf3a49c5110afea","lessThan":"1f06cfe0b60a878619d1d8efe1cd0f515b7dc2aa","status":"affected","versionType":"git"},{"version":"32dc0042528d385d83bf458e4cf3a49c5110afea","lessThan":"5a6bd62f09147b49b31fd19d4eba122cb5f941a1","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":"6.16","status":"affected"},{"version":"0","lessThan":"6.16","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":"6.16","versionEndExcluding":"6.18.60"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.2.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.3.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.4-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/92b69f6db640dadc0851762ee2e12db99f083cad"},{"url":"https://git.kernel.org/stable/c/d6d991afe775ab7fcf89523a2502b7ca3be56ffd"},{"url":"https://git.kernel.org/stable/c/1f06cfe0b60a878619d1d8efe1cd0f515b7dc2aa"},{"url":"https://git.kernel.org/stable/c/5a6bd62f09147b49b31fd19d4eba122cb5f941a1"}],"title":"tracing: Hold trace_types_lock when resetting last boot data from readers","x_generator":{"engine":"bippy-1.2.0"}}}}