# CVE-2026-99158: Linux kernel ring-buffer false warning in ring_buffer_map_get_reader

Source: https://junglewise.ai/threats/cve-2026-99158-in-the-linux-kernel-the-following-vulnerability-has-been-resolved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-28. Updated: 2026-10-28  
License: CC BY 4.0 with a link back

CVE-2026-99158 · Severity: info · Published 2026-10-28

The Linux kernel's ring buffer tracing component can emit a false warning when memory-mapped readers catch up with writers. This is a cosmetic issue—a spurious alert in diagnostic output—rather than a security vulnerability or denial-of-service condition that affects system operation.

Technologies: [Linux kernel](https://junglewise.ai/threats/technologies/x-linux-kernel).

## Quick answers

**Is CVE-2026-99158 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-99158 being exploited in the wild.

**How severe is CVE-2026-99158?** Informational severity, published 28 October 2026.

**Which products and versions are affected?** Linux kernel 5.0 and later (exact range not specified).

**Is there a fix for CVE-2026-99158?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-99158 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-99158?** Check whether you run Linux kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A race condition in ring_buffer_map_get_reader() causes it to treat a NULL return from rb_get_reader_page() as an error and warn, when the NULL is actually a benign result of the reader catching up with a writer that hasn't yet published committed data. The fix removes the erroneous WARN_ON() macro and instead handles the NULL case gracefully by exiting without warning, as the underlying reader-page helper already validates this condition.

## Affected products

- Linux kernel 5.0 and later (exact range not specified)

## Timeline

- 2026-10-28: disclosed

## References

- [https://git.kernel.org/stable/c/029770f5badedc0f0ff85fc45e24785cbbee4a67](https://git.kernel.org/stable/c/029770f5badedc0f0ff85fc45e24785cbbee4a67)
- [https://git.kernel.org/stable/c/68e6ab180cfb6dfa79652f41ed7899a6d4cf5438](https://git.kernel.org/stable/c/68e6ab180cfb6dfa79652f41ed7899a6d4cf5438)

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