{ "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": "2026-11-02T16:06:42.386Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-11-02T16:06:42.386Z" }, "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//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" } ] }, { "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" } ] } ], "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" } ] } ] } ], "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" } ], "title": "tracing: Hold trace_types_lock when resetting last boot data from readers", "x_generator": { "engine": "bippy-1.2.0" } } } }