CVE-2026-99158 ring-buffer: Fix false warning in ring_buffer_map_get_reader()
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-99158?
CVE-2026-99158 is a vulnerability in Linux, published on 28 Oct 2026.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Fix false warning in ring_buffer_map_get_reader()
The mmap reader can warn when it catches up with a writer that is still committing events. rb_get_reader_page() returns NULL in this case, but ring_buffer_map_get_reader() treats that result as an error.
The initial rb_per_cpu_empty() check filters out an empty buffer, but it does not guarantee that the next reader page has committed data. Writers do not take reader_lock and can advance commit_page before publishing the committed length on the new page. rb_get_reader_page() can swap to that page, catch up with the writer and return NULL.
Handle NULL through the existing no-data exit without warning. Remove the caller's reader_page == commit_page check as well, since the reader-page helper already handles that case. The existing metadata update and return path remain in place.
Which versions are affected by CVE-2026-99158?
How do I fix CVE-2026-99158?
Upgrade to a fixed version.
Is CVE-2026-99158 being exploited?
There is no known exploitation of CVE-2026-99158 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-99158, DEBIAN-CVE-2026-99158, GHSA-vq2v-33jv-5cr9, UBUNTU-CVE-2026-99158.