Vulnerability-Lookup

GHSA-H78F-R23H-V8HG

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: Make cpu_buffer::free_page a buffer_data_read_page

Discarding a cached reader page after a concurrent ring buffer resize uses the new global subbuf_order for the free_pages() call. This mismatched order may crashes the kernel or leaks memory because the cached page was allocated under the old size.

Save the actual free_page order alongside the page address to ensure we always refer to the correct value and do not rely on the potentially stalled cpu_buffer->subbuf_order value. The simplest is to make free_page a buffer_data_read_page which already covers exactly what we need: a page address and a page order.

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-2026-89500"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:32Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Make cpu_buffer::free_page a buffer_data_read_page\n\nDiscarding a cached reader page after a concurrent ring buffer resize\nuses the new global subbuf_order for the free_pages() call. This\nmismatched order may crashes the kernel or leaks memory because the cached\npage was allocated under the old size.\n\nSave the actual free_page order alongside the page address to ensure we\nalways refer to the correct value and do not rely on the potentially\nstalled cpu_buffer-\u003esubbuf_order value. The simplest is to make\nfree_page a buffer_data_read_page which already covers exactly what we\nneed: a page address and a page order.",
  "id": "GHSA-h78f-r23h-v8hg",
  "modified": "2026-09-13T09:32:14Z",
  "published": "2026-09-11T21:31:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89500"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7a1fb95de5404134f8758c1295ce88986bdf117c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a1dabe68fb53730bc0be60c5dbfd3f4c560084e7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d787d509bdf6c88c85e095247daf7456cb7fb772"
    }
  ],
  "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"
    }
  ]
}

CVE-2026-89500 (GCVE-0-2026-89500)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:43 – Updated: 2026-09-13 06:30

Title

ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page

Summary

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page Discarding a cached reader page after a concurrent ring buffer resize uses the new global subbuf_order for the free_pages() call. This mismatched order may crashes the kernel or leaks memory because the cached page was allocated under the old size. Save the actual free_page order alongside the page address to ensure we always refer to the correct value and do not rely on the potentially stalled cpu_buffer->subbuf_order value. The simplest is to make free_page a buffer_data_read_page which already covers exactly what we need: a page address and a page order.

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

3 references

URL	Tags
https://git.kernel.org/stable/c/a1dabe68fb53730bc…
https://git.kernel.org/stable/c/d787d509bdf6c88c8…
https://git.kernel.org/stable/c/7a1fb95de5404134f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8e7b58c27b3c567316a51079b375b846f9223bba , < a1dabe68fb53730bc0be60c5dbfd3f4c560084e7 (git) Affected: 8e7b58c27b3c567316a51079b375b846f9223bba , < d787d509bdf6c88c85e095247daf7456cb7fb772 (git) Affected: 8e7b58c27b3c567316a51079b375b846f9223bba , < 7a1fb95de5404134f8758c1295ce88986bdf117c (git)
Linux	Linux	Affected: 6.8 Unaffected: 0 , < 6.8 (semver) Unaffected: 6.18.51 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
  "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": "a1dabe68fb53730bc0be60c5dbfd3f4c560084e7",
              "status": "affected",
              "version": "8e7b58c27b3c567316a51079b375b846f9223bba",
              "versionType": "git"
            },
            {
              "lessThan": "d787d509bdf6c88c85e095247daf7456cb7fb772",
              "status": "affected",
              "version": "8e7b58c27b3c567316a51079b375b846f9223bba",
              "versionType": "git"
            },
            {
              "lessThan": "7a1fb95de5404134f8758c1295ce88986bdf117c",
              "status": "affected",
              "version": "8e7b58c27b3c567316a51079b375b846f9223bba",
              "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": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "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": "6.18.51",
                  "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: Make cpu_buffer::free_page a buffer_data_read_page\n\nDiscarding a cached reader page after a concurrent ring buffer resize\nuses the new global subbuf_order for the free_pages() call. This\nmismatched order may crashes the kernel or leaks memory because the cached\npage was allocated under the old size.\n\nSave the actual free_page order alongside the page address to ensure we\nalways refer to the correct value and do not rely on the potentially\nstalled cpu_buffer-\u003esubbuf_order value. The simplest is to make\nfree_page a buffer_data_read_page which already covers exactly what we\nneed: a page address and a page order."
        }
      ],
      "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 (buffer_subbuf_size_write -\u003e ring_buffer_subbuf_order_set) racing read/splice/close of per_cpu/cpuN/trace_pipe_raw (ring_buffer_alloc_read_page / ring_buffer_free_read_page) or instance rmdir (rb_free_cpu_buffer). No network, adjacent-radio, or physical path exists.\nAC:L - The attacker owns both sides of the race: one thread toggles buffer_subbuf_size_kb while another caches or discards a reader page via trace_pipe_raw. The window includes synchronize_rcu() and GFP_KERNEL allocation of every new sub-buffer, so the mismatch is reliably retryable with no condition outside attacker control.\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 is 0440; Android/Perfetto, ChromeOS, and distro tracing groups routinely delegate these to unprivileged accounts, matching CVE-2024-50207, CVE-2025-38101, and CVE-2026-74634.\nUI:N - Exploitation uses the attacker\u0027s own file descriptors and threads (write buffer_subbuf_size_kb, read/close trace_pipe_raw, optional instance rmdir). No separate victim mount, click, or configuration action is required.\nS:U - Wrong-order free_pages() and reuse of a cached reader page corrupt kernel ring-buffer and buddy-allocator pages within the same OS security authority. This enables local privilege escalation but does not cross VM, IOMMU, container, or hardware trust boundaries.\nC:H - cpu_buffer-\u003efree_page stored no allocation order, so a cached page allocated under the old subbuf size can be discarded or reused with the new order. Over-free and undersized-page swap are page UAF/OOB reads; recycled buddy pages and ring-buffer contents can be disclosed through subsequent trace_pipe_raw reads.\nI:H - free_pages() with a larger-than-allocated order returns neighboring in-use pages to the buddy allocator (page UAF/write). ring_buffer_read_page() can also swap that undersized cached page into the live writer path, producing out-of-bounds kernel stores exploitable for control-flow hijack.\nA:H - Mismatched-order free_pages() corrupts the buddy allocator and the commit states this may crash the kernel; UAF/OOB on ring-buffer pages also oops/panic. The attacker chooses the order delta via buffer_subbuf_size_kb and can retrigger the race at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:30:07.394Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a1dabe68fb53730bc0be60c5dbfd3f4c560084e7"
        },
        {
          "url": "https://git.kernel.org/stable/c/d787d509bdf6c88c85e095247daf7456cb7fb772"
        },
        {
          "url": "https://git.kernel.org/stable/c/7a1fb95de5404134f8758c1295ce88986bdf117c"
        }
      ],
      "title": "ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89500",
    "datePublished": "2026-09-11T19:43:49.392Z",
    "dateReserved": "2026-09-11T19:38:34.715Z",
    "dateUpdated": "2026-09-13T06:30:07.394Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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