FKIE_CVE-2026-89835

Vulnerability from fkie_nvd - Published: 2026-09-16 11:16 - Updated: 2026-09-16 11:16
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
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a6573f3ffc19542de9ebc1a2b1f930fd48ba538c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/aefcec3bebdeed2bff444378122300763325ba23
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/sysfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a6573f3ffc19542de9ebc1a2b1f930fd48ba538c",
              "status": "affected",
              "version": "e65920661708b7c0f3db45c9cd5d0095034ee37f",
              "versionType": "git"
            },
            {
              "lessThan": "aefcec3bebdeed2bff444378122300763325ba23",
              "status": "affected",
              "version": "e65920661708b7c0f3db45c9cd5d0095034ee37f",
              "versionType": "git"
            },
            {
              "lessThan": "8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b",
              "status": "affected",
              "version": "e65920661708b7c0f3db45c9cd5d0095034ee37f",
              "versionType": "git"
            },
            {
              "lessThan": "5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f",
              "status": "affected",
              "version": "e65920661708b7c0f3db45c9cd5d0095034ee37f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/sysfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.12"
            },
            {
              "lessThan": "5.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "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\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."
    }
  ],
  "id": "CVE-2026-89835",
  "lastModified": "2026-09-16T11:16:50.290",
  "metrics": {},
  "published": "2026-09-16T11:16:50.290",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a6573f3ffc19542de9ebc1a2b1f930fd48ba538c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/aefcec3bebdeed2bff444378122300763325ba23"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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