In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Fix the sub-buffer array base in rb_meta_subbuf_idx()
On a persistent ring buffer, rb_meta_subbuf_idx() can return an index one
sub-buffer too high. rb_setup_ids_meta_page() then fills subbuf_ids[]
shifted by one and leaves subbuf_ids[0] NULL, which __rb_map_vma()
dereferences when userspace maps trace_pipe_raw. rb_update_meta_reader()
writes two such indices into meta->buffers[], which rb_cpu_meta_valid()
would reject on the next boot, discarding the previous boot's trace.
A CPU's sub-buffer array starts after its meta header and the nr_subbufs
integers that follow, aligned up to a sub-buffer. rb_meta_subbuf_idx()
inverts that calculation but skips only the integers, not the header, so
its base is one sub-buffer low whenever the omitted header size crosses
the alignment boundary.
Invert the calculation with rb_subbufs_from_meta() rather than repeating
it. rb_range_buffer() maps an index back to an address through the same
helper, so the two directions can no longer disagree.
Metrics
Affected Vendors & Products
| Vendors | Products |
|---|---|
| Linux |
|
No data.
No data.
References
History
Wed, 28 Oct 2026 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux linux
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| Vendors & Products |
Linux linux
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Wed, 28 Oct 2026 13:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-129 CWE-476 |
Wed, 28 Oct 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
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| Description | In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix the sub-buffer array base in rb_meta_subbuf_idx() On a persistent ring buffer, rb_meta_subbuf_idx() can return an index one sub-buffer too high. rb_setup_ids_meta_page() then fills subbuf_ids[] shifted by one and leaves subbuf_ids[0] NULL, which __rb_map_vma() dereferences when userspace maps trace_pipe_raw. rb_update_meta_reader() writes two such indices into meta->buffers[], which rb_cpu_meta_valid() would reject on the next boot, discarding the previous boot's trace. A CPU's sub-buffer array starts after its meta header and the nr_subbufs integers that follow, aligned up to a sub-buffer. rb_meta_subbuf_idx() inverts that calculation but skips only the integers, not the header, so its base is one sub-buffer low whenever the omitted header size crosses the alignment boundary. Invert the calculation with rb_subbufs_from_meta() rather than repeating it. rb_range_buffer() maps an index back to an address through the same helper, so the two directions can no longer disagree. | |
| Title | ring-buffer: Fix the sub-buffer array base in rb_meta_subbuf_idx() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2026-10-28T10:35:12.520Z
Updated: 2026-10-28T10:35:12.520Z
Reserved: 2026-09-25T10:25:14.397Z
Link: CVE-2026-99159
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-28T11:17:36.160
Modified: 2026-10-28T11:17:36.160
Link: CVE-2026-99159
Redhat
No data.