{"id":"CVE-2026-74601","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Use current_context for safe per-CPU buffer swap\n\nThe ring_buffer_swap_cpu() function currently checks the per-CPU\ncommitting counter to determine if a buf…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Use current_context for safe per-CPU buffer swap\n\nThe ring_buffer_swap_cpu() function currently checks the per-CPU\ncommitting counter to determine if a buf…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","published":"2026-08-22","updated":"2026-10-14","sourceUpdated":"2026-10-14T13:10:00.187","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74601","references":[{"url":"https://git.kernel.org/stable/c/22709117d9ae95e52673685f98caac7c356a8227","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/26662bc8fced1d668fa1aa146eda085bfc67bd0b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/597f279b7b4a06412e3d965e98cc36e181cdbede","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5e6e2a18c20e88167d414f666032792e8bf19b80","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6b524e6b234e45c7f5f90d13b042c6f57f80105c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ad7e10c7ea89af45ac1bf1814855d45da472703d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f27bdc43077e4fcb5557dfc315ee8d91e741f483","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00136,"epssPercentile":0.02625,"ingestedAt":"2026-10-14T13:30:58.512Z","slug":"CVE-2026-74601","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Use current_context for safe per-CPU buffer swap\n\nThe ring_buffer_swap_cpu() function currently checks the per-CPU\ncommitting counter to determine if a buffer is actively being written to\nbefore performing the swap. However, there exists a race window where\nthis check can be bypassed:\n\n    ring_buffer_lock_reserve\n        cpu_buffer = buffer->buffers[cpu];       // cpu_buffer_a\n        rb_reserve_next_event\n            rb_start_commit // inc committing\n            if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}\n            __rb_reserve_next\n                rb_move_tail\n                    rb_end_commit(cpu_buffer);   // dec committing => 0\n                    /* interrupt hits here, successfully swaps! */\n                    local_inc(&cpu_buffer->committing);\n\n    ring_buffer_unlock_commit\n        cpu_buffer = buffer->buffers[cpu];      // cpu_buffer_b\n        rb_commit\n            rb_end_commit\n            RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))\n                                                // triggers warning\n\nThe committing counter can temporarily drop to 0 during a single write\noperation (within rb_move_tail), creating a window where swap can\nsucceed even though the write is still in progress. This leads to\ninconsistent buffer state and triggers the RB_WARN_ON in rb_commit().\n\nReplace the committing counter check with current_context checks, which\nare set at the entry of ring_buffer_lock_reserve() and remain valid\nthroughout the entire write operation, providing a reliable indicator of\nbuffer busy state during swap.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}