tracing: Fix use-after-free in trace_pipe read on sub-buffer order change

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89747
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:20:05 UTC
Updated2026-09-11 20:20:05 UTC
DescriptionIn 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.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected f9b94daa542a8d2532f0930f01cd9aec2d19621b 05ebe1e1d7d38c2612bacfefe043a33572ae34cb git Not specified
CNA Linux Linux affected f9b94daa542a8d2532f0930f01cd9aec2d19621b ddbe921ed16a0ad2d9e09574c3f3aabec7528325 git Not specified
CNA Linux Linux affected f9b94daa542a8d2532f0930f01cd9aec2d19621b 7a49d19ff9baaf61217e5ec14199c18bc2d93ee4 git Not specified
CNA Linux Linux affected f9b94daa542a8d2532f0930f01cd9aec2d19621b 372f8534244d632ad5118e8a87a11291b01712d3 git Not specified
CNA Linux Linux affected 6.8 Not specified
CNA Linux Linux unaffected 6.8 semver Not specified
CNA Linux Linux unaffected 6.12.109 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.50 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/372f8534244d632ad5118e8a87a11291b01712d3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/05ebe1e1d7d38c2612bacfefe043a33572ae34cb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7a49d19ff9baaf61217e5ec14199c18bc2d93ee4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ddbe921ed16a0ad2d9e09574c3f3aabec7528325 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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