FKIE_CVE-2026-74601

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/22709117d9ae95e52673685f98caac7c356a8227
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/26662bc8fced1d668fa1aa146eda085bfc67bd0b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/597f279b7b4a06412e3d965e98cc36e181cdbede
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5e6e2a18c20e88167d414f666032792e8bf19b80
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b524e6b234e45c7f5f90d13b042c6f57f80105c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ad7e10c7ea89af45ac1bf1814855d45da472703d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f27bdc43077e4fcb5557dfc315ee8d91e741f483
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/trace/ring_buffer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "26662bc8fced1d668fa1aa146eda085bfc67bd0b",
              "status": "affected",
              "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
              "versionType": "git"
            },
            {
              "lessThan": "6b524e6b234e45c7f5f90d13b042c6f57f80105c",
              "status": "affected",
              "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
              "versionType": "git"
            },
            {
              "lessThan": "597f279b7b4a06412e3d965e98cc36e181cdbede",
              "status": "affected",
              "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
              "versionType": "git"
            },
            {
              "lessThan": "22709117d9ae95e52673685f98caac7c356a8227",
              "status": "affected",
              "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
              "versionType": "git"
            },
            {
              "lessThan": "ad7e10c7ea89af45ac1bf1814855d45da472703d",
              "status": "affected",
              "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
              "versionType": "git"
            },
            {
              "lessThan": "5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f",
              "status": "affected",
              "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
              "versionType": "git"
            },
            {
              "lessThan": "5e6e2a18c20e88167d414f666032792e8bf19b80",
              "status": "affected",
              "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
              "versionType": "git"
            },
            {
              "lessThan": "f27bdc43077e4fcb5557dfc315ee8d91e741f483",
              "status": "affected",
              "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/trace/ring_buffer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.5"
            },
            {
              "lessThan": "4.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.266",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.217",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.184",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.153",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.105",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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 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-\u003ebuffers[cpu];       // cpu_buffer_a\n        rb_reserve_next_event\n            rb_start_commit // inc committing\n            if (unlikely(READ_ONCE(cpu_buffer-\u003ebuffer) != buffer)) {...}\n            __rb_reserve_next\n                rb_move_tail\n                    rb_end_commit(cpu_buffer);   // dec committing =\u003e 0\n                    /* interrupt hits here, successfully swaps! */\n                    local_inc(\u0026cpu_buffer-\u003ecommitting);\n\n    ring_buffer_unlock_commit\n        cpu_buffer = buffer-\u003ebuffers[cpu];      // cpu_buffer_b\n        rb_commit\n            rb_end_commit\n            RB_WARN_ON(cpu_buffer, !local_read(\u0026cpu_buffer-\u003ecommitting))\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."
    }
  ],
  "id": "CVE-2026-74601",
  "lastModified": "2026-08-25T06:18:36.057",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:32.530",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/22709117d9ae95e52673685f98caac7c356a8227"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/26662bc8fced1d668fa1aa146eda085bfc67bd0b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/597f279b7b4a06412e3d965e98cc36e181cdbede"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5e6e2a18c20e88167d414f666032792e8bf19b80"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b524e6b234e45c7f5f90d13b042c6f57f80105c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ad7e10c7ea89af45ac1bf1814855d45da472703d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f27bdc43077e4fcb5557dfc315ee8d91e741f483"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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