Vulnerability-Lookup

CVE-2026-89771 (GCVE-0-2026-89771)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:47 – Updated: 2026-09-13 06:34

Title

ring-buffer: Fix subbuf resize race with ring buffer readers

Summary

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix subbuf resize race with ring buffer readers trace_buffer subbuf_size is read lockless in ring_buffer_read_page() and ring_buffer_read_start(), while it can simultaneously be resized with ring_buffer_subbuf_order_set(). Instead of trace_buffer::subbuf_size, use bpage::order in ring_buffer_read_start() and ring_buffer_read_page(). In ring_buffer_read_start(), even with resize_disabled, there is still a possibility of a race with a buffer modification. Hold the trace_buffer mutex to synchronise with any pending ring buffer order modification. trace_buffer::subbuf_size is now actually useless, remove it. Also, create accessors rb_subbuf_capacity() and rb_page_capacity() which return the actual size available for storing events, while rb_subbuf_size() returns the actual subbuf page-size.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/6d666f0b8b36c0765…
https://git.kernel.org/stable/c/50f4a793c4ff24826…
https://git.kernel.org/stable/c/0c7c517827a453128…
https://git.kernel.org/stable/c/8a5f63637890f0317…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: f9b94daa542a8d2532f0930f01cd9aec2d19621b , < 6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9 (git) Affected: f9b94daa542a8d2532f0930f01cd9aec2d19621b , < 50f4a793c4ff24826efb0ac700989a5063cc53df (git) Affected: f9b94daa542a8d2532f0930f01cd9aec2d19621b , < 0c7c517827a453128a8f58bfd849546a29813b27 (git) Affected: f9b94daa542a8d2532f0930f01cd9aec2d19621b , < 8a5f63637890f03177146efddaba5ec7a1b4d61f (git)	guessed
Linux	Linux	Affected: 6.8 Unaffected: 0 , < 6.8 (semver) Unaffected: 6.12.109 , ≤ 6.12.* (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "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": "6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9",
              "status": "affected",
              "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
              "versionType": "git"
            },
            {
              "lessThan": "50f4a793c4ff24826efb0ac700989a5063cc53df",
              "status": "affected",
              "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "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": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix subbuf resize race with ring buffer readers\n\ntrace_buffer subbuf_size is read lockless in ring_buffer_read_page() and\nring_buffer_read_start(), while it can simultaneously be resized with\nring_buffer_subbuf_order_set().\n\nInstead of trace_buffer::subbuf_size, use bpage::order in\nring_buffer_read_start() and ring_buffer_read_page().\n\nIn ring_buffer_read_start(), even with resize_disabled, there is still a\npossibility of a race with a buffer modification. Hold the trace_buffer\nmutex to synchronise with any pending ring buffer order modification.\n\ntrace_buffer::subbuf_size is now actually useless, remove it. Also,\ncreate accessors rb_subbuf_capacity() and rb_page_capacity() which\nreturn the actual size available for storing events, while\nrb_subbuf_size() returns the actual subbuf page-size."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only via local tracefs: write() to buffer_subbuf_size_kb (ring_buffer_subbuf_order_set) racing with read()/splice() of per_cpu/*/trace_pipe_raw (ring_buffer_read_page) or open/read of trace (ring_buffer_read_start). No network, adjacent-radio, or physical path exists.\nAC:L - The attacker controls both sides: one thread writes buffer_subbuf_size_kb while another reads trace_pipe_raw or trace. ring_buffer_subbuf_order_set publishes the new subbuf_size before allocating replacement pages and without reader_lock, so the window includes synchronize_rcu() plus GFP_KERNEL allocation and is reliably retried.\nPR:L - tracing_check_open_get_tr() enforces only LOCKDOWN_TRACEFS and DAC with no capable() check. buffer_subbuf_size_kb is 0640 and trace_pipe_raw/trace are 0440/0640, routinely delegated via tracefs gid=/mode= to tracing-group members on Android/Perfetto, ChromeOS, and developer systems, matching CVE-2024-50207 and CVE-2026-74634.\nUI:N - Exploitation uses the attacker\u0027s own tracefs file descriptors and threads (write buffer_subbuf_size_kb while reading trace_pipe_raw or trace). No separate victim mount, click, or configuration action is required.\nS:U - The out-of-bounds memset/memcpy corrupt kernel ring-buffer pages and adjacent heap within the same OS security authority. This enables local privilege escalation but does not cross VM, IOMMU, container, or hardware trust boundaries.\nC:H - ring_buffer_read_page() uses the lockless new subbuf_size to memset/memcpy past an old-order spare or reader page, and tracing_buffers_read copy_to_user of that oversized length discloses adjacent kernel heap to userspace. The same OOB corruption is also a high-impact read primitive.\nI:H - After a passing order check, ring_buffer_read_page() memset()s (new_subbuf_size-size) bytes past the still-old data page (up to hundreds of KB when order jumps 0 to 7). That kernel heap OOB write is exploitable for arbitrary writes and control-flow hijack, not merely a crash.\nA:H - The same OOB memset/memcpy corrupt adjacent kernel objects and ring-buffer metadata, producing oops/panic. The attacker chooses the order delta via buffer_subbuf_size_kb and can retrigger the race at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:34:12.518Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9"
        },
        {
          "url": "https://git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df"
        },
        {
          "url": "https://git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27"
        },
        {
          "url": "https://git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f"
        }
      ],
      "title": "ring-buffer: Fix subbuf resize race with ring buffer readers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89771",
    "datePublished": "2026-09-11T19:47:10.381Z",
    "dateReserved": "2026-09-11T19:38:34.765Z",
    "dateUpdated": "2026-09-13T06:34:12.518Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-89771",
      "date": "2026-09-12",
      "epss": "0.00156",
      "percentile": "0.0512"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-89771\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-11T20:20:08.460\",\"lastModified\":\"2026-09-13T07:17:41.310\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nring-buffer: Fix subbuf resize race with ring buffer readers\\n\\ntrace_buffer subbuf_size is read lockless in ring_buffer_read_page() and\\nring_buffer_read_start(), while it can simultaneously be resized with\\nring_buffer_subbuf_order_set().\\n\\nInstead of trace_buffer::subbuf_size, use bpage::order in\\nring_buffer_read_start() and ring_buffer_read_page().\\n\\nIn ring_buffer_read_start(), even with resize_disabled, there is still a\\npossibility of a race with a buffer modification. Hold the trace_buffer\\nmutex to synchronise with any pending ring buffer order modification.\\n\\ntrace_buffer::subbuf_size is now actually useless, remove it. Also,\\ncreate accessors rb_subbuf_capacity() and rb_page_capacity() which\\nreturn the actual size available for storing events, while\\nrb_subbuf_size() returns the actual subbuf page-size.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"kernel/trace/ring_buffer.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"f9b94daa542a8d2532f0930f01cd9aec2d19621b\",\"lessThan\":\"6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f9b94daa542a8d2532f0930f01cd9aec2d19621b\",\"lessThan\":\"50f4a793c4ff24826efb0ac700989a5063cc53df\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f9b94daa542a8d2532f0930f01cd9aec2d19621b\",\"lessThan\":\"0c7c517827a453128a8f58bfd849546a29813b27\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f9b94daa542a8d2532f0930f01cd9aec2d19621b\",\"lessThan\":\"8a5f63637890f03177146efddaba5ec7a1b4d61f\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"kernel/trace/ring_buffer.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.8\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.8\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.109\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.50\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-13T06:53:08+00:00",
      "cve": "CVE-2026-89771",
      "id": "CVE-2026-89771",
      "initial_release_date": "2026-09-11T19:47:10.381000+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: Race condition in ring buffer resizing can lead to denial of service.",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89771.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-09-12T16:21:44Z",
      "cve": "CVE-2026-89771",
      "id": "CVE-2026-89771",
      "initial_release_date": "2026-09-12T16:21:44Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89771",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89771.json",
      "version": "2"
    }
  }
}

FKIE_CVE-2026-89771

Vulnerability from fkie_nvd - Published: 2026-09-11 20:20 - Updated: 2026-09-13 07:17

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f

Impacted products

	Vendor	Product	Version

JSON

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": "6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9",
              "status": "affected",
              "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
              "versionType": "git"
            },
            {
              "lessThan": "50f4a793c4ff24826efb0ac700989a5063cc53df",
              "status": "affected",
              "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
              "versionType": "git"
            },
            {
              "lessThan": "0c7c517827a453128a8f58bfd849546a29813b27",
              "status": "affected",
              "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
              "versionType": "git"
            },
            {
              "lessThan": "8a5f63637890f03177146efddaba5ec7a1b4d61f",
              "status": "affected",
              "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
              "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": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "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: Fix subbuf resize race with ring buffer readers\n\ntrace_buffer subbuf_size is read lockless in ring_buffer_read_page() and\nring_buffer_read_start(), while it can simultaneously be resized with\nring_buffer_subbuf_order_set().\n\nInstead of trace_buffer::subbuf_size, use bpage::order in\nring_buffer_read_start() and ring_buffer_read_page().\n\nIn ring_buffer_read_start(), even with resize_disabled, there is still a\npossibility of a race with a buffer modification. Hold the trace_buffer\nmutex to synchronise with any pending ring buffer order modification.\n\ntrace_buffer::subbuf_size is now actually useless, remove it. Also,\ncreate accessors rb_subbuf_capacity() and rb_page_capacity() which\nreturn the actual size available for storing events, while\nrb_subbuf_size() returns the actual subbuf page-size."
    }
  ],
  "id": "CVE-2026-89771",
  "lastModified": "2026-09-13T07:17:41.310",
  "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": "2026-09-11T20:20:08.460",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-8MW5-WV48-MPHH

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-13 09:32

Details

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

ring-buffer: Fix subbuf resize race with ring buffer readers

trace_buffer subbuf_size is read lockless in ring_buffer_read_page() and ring_buffer_read_start(), while it can simultaneously be resized with ring_buffer_subbuf_order_set().

Instead of trace_buffer::subbuf_size, use bpage::order in ring_buffer_read_start() and ring_buffer_read_page().

In ring_buffer_read_start(), even with resize_disabled, there is still a possibility of a race with a buffer modification. Hold the trace_buffer mutex to synchronise with any pending ring buffer order modification.

trace_buffer::subbuf_size is now actually useless, remove it. Also, create accessors rb_subbuf_capacity() and rb_page_capacity() which return the actual size available for storing events, while rb_subbuf_size() returns the actual subbuf page-size.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89771"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:20:08Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix subbuf resize race with ring buffer readers\n\ntrace_buffer subbuf_size is read lockless in ring_buffer_read_page() and\nring_buffer_read_start(), while it can simultaneously be resized with\nring_buffer_subbuf_order_set().\n\nInstead of trace_buffer::subbuf_size, use bpage::order in\nring_buffer_read_start() and ring_buffer_read_page().\n\nIn ring_buffer_read_start(), even with resize_disabled, there is still a\npossibility of a race with a buffer modification. Hold the trace_buffer\nmutex to synchronise with any pending ring buffer order modification.\n\ntrace_buffer::subbuf_size is now actually useless, remove it. Also,\ncreate accessors rb_subbuf_capacity() and rb_page_capacity() which\nreturn the actual size available for storing events, while\nrb_subbuf_size() returns the actual subbuf page-size.",
  "id": "GHSA-8mw5-wv48-mphh",
  "modified": "2026-09-13T09:32:30Z",
  "published": "2026-09-11T21:31:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89771"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-89771 (GCVE-0-2026-89771)

FKIE_CVE-2026-89771

GHSA-8MW5-WV48-MPHH

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Nomenclature