CVE-2025-68186: ring-buffer: Do not warn in ring_buffer_map_get_reader() when reader catches up
In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Do not warn in ringbuffermapgetreader() when reader catches up
The function ringbuffermapgetreader() is a bit more strict than the other get reader functions, and except for certain situations the rbgetreaderpage() should not return NULL. If it does, it triggers a warning.
This warning was triggering but after looking at why, it was because another acceptable situation was happening and it wasn't checked for.
If the reader catches up to the writer and there's still data to be read on the reader page, then the rbgetreaderpage() will return NULL as there's no new page to get.
In this situation, the reader page should not be updated and no warning should trigger.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-68186?
CVE-2025-68186 is classified as a moderate severity vulnerability in the Linux kernel.
How does CVE-2025-68186 affect the Linux kernel?
CVE-2025-68186 affects the ring buffer management in the Linux kernel, potentially leading to improper handling of reader synchronization.
How do I fix CVE-2025-68186?
To fix CVE-2025-68186, update your Linux kernel to the latest stable version that includes the patch for this vulnerability.
What are the potential impacts of exploiting CVE-2025-68186?
Exploiting CVE-2025-68186 could result in unexpected behavior in the ring buffer, but it does not provide an avenue for remote code execution.
When was CVE-2025-68186 reported?
CVE-2025-68186 was reported as a vulnerability in the Linux kernel affecting the proper handling of readers in the ring buffer.