CVE-2026-89835 (GCVE-0-2026-89835)
Vulnerability from cvelistv5
Published
2026-09-16 10:31
Modified
2026-10-21 12:48
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: avoid NULL checkpoint thread access in sysfs checkpoint_merge can be enabled even when no checkpoint merge thread is running. A read-only mount is one case: f2fs does not start f2fs_issue_ckpt there, but ckpt_thread_ioprio is still writable through sysfs. The ckpt_thread_ioprio store path updates the saved ioprio value and, when checkpoint_merge is enabled, calls set_task_ioprio() for the checkpoint thread. If cprc->f2fs_issue_ckpt is NULL, that dereferences a NULL task pointer. Protect ckpt_thread_ioprio sysfs writes with s_umount as well, so the checkpoint thread cannot disappear under the store path while updating its ioprio.
References
Impacted products
Vendor Product Version
Linux Linux Version: e65920661708b7c0f3db45c9cd5d0095034ee37f
Version: e65920661708b7c0f3db45c9cd5d0095034ee37f
Version: e65920661708b7c0f3db45c9cd5d0095034ee37f
Version: e65920661708b7c0f3db45c9cd5d0095034ee37f
Version: e65920661708b7c0f3db45c9cd5d0095034ee37f
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/sysfs.c"
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          "programFiles": [
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          "vendor": "Linux",
          "versions": [
            {
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              "version": "5.12"
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              "versionType": "semver"
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              "version": "6.18.51",
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              "version": "7.2.5",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: avoid NULL checkpoint thread access in sysfs\n\ncheckpoint_merge can be enabled even when no checkpoint merge thread is\nrunning. A read-only mount is one case: f2fs does not start\nf2fs_issue_ckpt there, but ckpt_thread_ioprio is still writable through\nsysfs.\n\nThe ckpt_thread_ioprio store path updates the saved ioprio value and,\nwhen checkpoint_merge is enabled, calls set_task_ioprio() for the\ncheckpoint thread. If cprc-\u003ef2fs_issue_ckpt is NULL, that dereferences a\nNULL task pointer.\n\nProtect ckpt_thread_ioprio sysfs writes with s_umount as well, so the\ncheckpoint thread cannot disappear under the store path while updating\nits ioprio."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:48:58.936Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/22760e3e9cecbddc475edc91600787abf407a302"
        },
        {
          "url": "https://git.kernel.org/stable/c/a6573f3ffc19542de9ebc1a2b1f930fd48ba538c"
        },
        {
          "url": "https://git.kernel.org/stable/c/aefcec3bebdeed2bff444378122300763325ba23"
        },
        {
          "url": "https://git.kernel.org/stable/c/8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b"
        },
        {
          "url": "https://git.kernel.org/stable/c/5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f"
        }
      ],
      "title": "f2fs: avoid NULL checkpoint thread access in sysfs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89835",
    "datePublished": "2026-09-16T10:31:08.636Z",
    "dateReserved": "2026-09-11T19:38:34.769Z",
    "dateUpdated": "2026-10-21T12:48:58.936Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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