High [CVE-2026-53189] update file PMD counter before folio_put
This high-severity Red Hat Linux advisory covers CVE-2026-53189 affecting Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 10.
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Summary
In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: update file PMD counter before folio_put() __split_huge_pmd_locked() updates the file/shmem RSS counter after dropping the PMD mapping's folio reference. If folio_put() drops the last reference, mm_counter_file() can later read freed folio state via folio_test_swapbacked().
A flaw was found in the Linux kernel's memory management, specifically within the huge page mechanism. When a huge page is split, the system updates a counter after releasing a reference to the memory.
This timing issue can lead to the system attempting to read from memory that has already been freed, potentially resulting in memory corruption or information disclosure. Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H).
Weakness: CWE-364. Affected Red Hat products: Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Enterprise Linux 10.
Red Hat fixing advisory: RHSA-2026:57254, RHSA-2026:57253, RHSA-2026:57252.
Affected products named by the advisory: Red Hat package: kernel-rt.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 13 days ago·verify at source
- kernel-rt-0:4.18.0-553.157.1.rt7.498.el8_10
- kernel-0:4.18.0-553.157.1.el8_10
- kernel-0:5.14.0-687.41.1.el9_8
- RHSA-2026:57254
- RHSA-2026:57253
- RHSA-2026:57252
Official advisory · high-confidence parse· fetched 13 days ago·verify at source
Mitigation
Upgrade to a fixed release: kernel-rt-0:4.18.0-553.157.1.rt7.498.el8_10, kernel-0:4.18.0-553.157.1.el8_10, kernel-0:5.14.0-687.41.1.el9_8, RHSA-2026:57254, RHSA-2026:57253, RHSA-2026:57252. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 13 days ago·verify at source
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