CVE-2026-90002
HighCVSS 7.8Summary
A use-after-free bug exists in the Linux kernel ftrace subsystem. The set_ftrace_filter and set_ftrace_notrace files for trace instances use the ftrace_ops pointer from inode->private, which can be freed concurrently by an rmdir on the instance, leading to a use-after-free and kernel crash.
Risk Assessment
A local user able to manipulate ftrace instances (creating/removing instance directories and opening filter files) can trigger a kernel crash (denial of service) and potentially exploit the bug for privilege escalation under favorable conditions.
Recommendation
Update the Linux kernel to a version containing the fix that passes trace_array as file private data and takes a reference before touching ftrace_ops. Until patched, restrict access to /sys/kernel/tracing to untrusted users.
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- CVE-2026-100073Unknown
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- CVE-2026-100072Unknown
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Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: ftrace: Take trace_array reference before accessing its ftrace_ops The trace instance files set_ftrace_filter and set_ftrace_notrace was updated to work with specific trace instances (trace_arrays). The issue is that when these files are opened, there is a small race window where it will use the ftrace_ops from the inode->private pointer to get a reference to the trace_array and then take its reference. The problem is that the ftrace_ops itself could be freed. If the rmdir on the instance happens at the same time the set_ftrace_filter file is opened, the rmdir could have also freed the ftrace_ops and referencing it will cause a use-after-free bug and crash the kernel. Instead, pass in the trace_array as the file private data (NULL for the top level instance), and then pass both the trace_array and the ftrace_ops to the ftrace_regex_open() function. If the trace_array is NULL, then it just uses the ftrace_ops without the need to take its reference (like normal). If the ftrace_ops is NULL, that is only the case for the top level instance and the global_ops can be used. This allows the trace_array to have its reference incremented before touching the ftrace_ops that could also be freed when the instance is.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS