CVE-2026-89747
CVE-2026-89747 is a security vulnerability. O3 Security confirms whether CVE-2026-89747 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix use-after-free in trace_pipe read on sub-buffer order change Writing to buffer_subbuf_size_kb calls…
Description
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
Writing to buffer_subbuf_size_kb calls ring_buffer_subbuf_order_set(), which frees every sub-buffer of the ring buffer, including the reader page, and replaces them with newly allocated ones.
Readers of trace_pipe hold pointers into those pages. ring_buffer_peek() looks up an event under cpu_buffer->reader_lock but returns the event pointer after dropping the lock, and peek_next_entry() then calls ring_buffer_event_length() and ring_buffer_event_data() on it. If the sub-buffer order is changed in that window, the reader dereferences freed memory:
BUG: KASAN: use-after-free in ring_buffer_peek+0x3e0/0x430 Read of size 1 at addr ffff88802a4cf010 by task syz-executor989/6002
Freed by: free_buffer_page kernel/trace/ring_buffer.c:398 [inline] ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444 buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221
Take trace_access_lock(RING_BUFFER_ALL_CPUS) around the order change. This is the lock trace_pipe readers already hold across their entire peek-and-print loop, so the swap can no longer race with a reader that is dereferencing a peeked event.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-89747 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-89747 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-89747. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-89747 in your dependencies?
O3 detects CVE-2026-89747 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.