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CVE-2026-74601

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

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 · fixed in 26662bc8fced1d668fa1aa146eda085bfc67bd0b; From 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 · fixed in 6b524e6b234e45c7f5f90d13b042c6f57f80105c; From 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 · fixed in 597f279b7b4a06412e3d965e98cc36e181cdbede; From 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 · fixed in 22709117d9ae95e52673685f98caac7c356a8227; From 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 · fixed in ad7e10c7ea89af45ac1bf1814855d45da472703d; From 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 · fixed in 5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f; From 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 · fixed in 5e6e2a18c20e88167d414f666032792e8bf19b80; From 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 · fixed in f27bdc43077e4fcb5557dfc315ee8d91e741f483

  • Linux Linux

    4.5

  • KernelLinux

    From 4.5.0 · fixed in 5.10.266; From 5.11.0 · fixed in 5.15.217; From 5.16.0 · fixed in 6.1.184; From 6.2.0 · fixed in 6.6.153; From 6.7.0 · fixed in 6.12.105; From 6.13.0 · fixed in 6.18.45; From 6.19.0 · fixed in 7.1.9

References 8

git.kernel.org