Homepage

Time-of-check Time-of-use (TOCTOU) Affecting kernel-rt-devel package, versions *

Severity

 Recommended
low

Based on CentOS security rating.

Threat Intelligence

EPSS
0.14% (4th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-CENTOS10-KERNELRTDEVEL-19260263
  • published26 Aug 2026
  • disclosed22 Aug 2026
Report a new vulnerability Found a mistake?

Introduced: 22 Aug 2026

NewCVE-2026-74601  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel-rt-devel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-devel package and not the kernel-rt-devel package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

ring-buffer: Use current_context for safe per-CPU buffer swap

The ring_buffer_swap_cpu() function currently checks the per-CPU committing counter to determine if a buffer is actively being written to before performing the swap. However, there exists a race window where this check can be bypassed:

ring_buffer_lock_reserve
    cpu_buffer = buffer->buffers[cpu];       // cpu_buffer_a
    rb_reserve_next_event
        rb_start_commit // inc committing
        if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
        __rb_reserve_next
            rb_move_tail
                rb_end_commit(cpu_buffer);   // dec committing => 0
                /* interrupt hits here, successfully swaps! */
                local_inc(&cpu_buffer->committing);


ring_buffer_unlock_commit
    cpu_buffer = buffer->buffers[cpu];      // cpu_buffer_b
    rb_commit
        rb_end_commit
        RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
                                            // triggers warning

The committing counter can temporarily drop to 0 during a single write operation (within rb_move_tail), creating a window where swap can succeed even though the write is still in progress. This leads to inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().

Replace the committing counter check with current_context checks, which are set at the entry of ring_buffer_lock_reserve() and remain valid throughout the entire write operation, providing a reliable indicator of buffer busy state during swap.

CVSS Base Scores

version 3.1