CVE-2026-89835 (GCVE-0-2026-89835)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:31 – Updated: 2026-10-30 12:33
VLAI
Title
f2fs: avoid NULL checkpoint thread access in sysfs
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.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6639 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: e65920661708b7c0f3db45c9cd5d0095034ee37f , < 54196bcfde998fb37009f50e0ef16498f651f0f9 (git)
Affected: e65920661708b7c0f3db45c9cd5d0095034ee37f , < 22760e3e9cecbddc475edc91600787abf407a302 (git)
Affected: e65920661708b7c0f3db45c9cd5d0095034ee37f , < a6573f3ffc19542de9ebc1a2b1f930fd48ba538c (git)
Affected: e65920661708b7c0f3db45c9cd5d0095034ee37f , < aefcec3bebdeed2bff444378122300763325ba23 (git)
Affected: e65920661708b7c0f3db45c9cd5d0095034ee37f , < 8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b (git)
Affected: e65920661708b7c0f3db45c9cd5d0095034ee37f , < 5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f (git)
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Linux Linux Affected: 5.12
Unaffected: 0 , < 5.12 (semver)
Unaffected: 6.1.191 , ≤ 6.1.* (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.51 , ≤ 6.18.* (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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          }
        ],
        "id": "CVE-2026-89835",
        "lastModified": "2026-10-30T13:20:30.740",
        "metrics": {},
        "published": "2026-09-16T11:16:50.290",
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      "current_release_date": "2026-11-06T01:24:24+00:00",
      "cve": "CVE-2026-89835",
      "id": "CVE-2026-89835",
      "initial_release_date": "2026-09-16T00:00:00+00:00",
      "product_status:known_not_affected": "203",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: f2fs: avoid NULL checkpoint thread access in sysfs",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89835.json",
      "version": "3"
    }
  }
}



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