Linux: Use After Free
CVE-2026-53189 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 84b3212b166b446faea27ebebb7161405ffceef9, 108963978a681c0c468d279cac2b930c27672877, 459771c9cf30f378bdbd30fc65d17f7eb931bb59 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 84b3212b166b446faea27ebebb7161405ffceef9 or 108963978a681c0c468d279cac2b930c27672877 or 459771c9cf30f378bdbd30fc65d17f7eb931bb59 or ae9d4caf6f133e884cf5fcda4982c493b35e5194, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.176 or 6.6.143, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | fadae2953072e9005c5f1d64e1049edb043494dc up to, but not including, 84b3212b166b446faea27ebebb7161405ffceef9; fadae2953072e9005c5f1d64e1049edb043494dc up to, but not including, 108963978a681c0c468d279cac2b930c27672877; fadae2953072e9005c5f1d64e1049edb043494dc up to, but not including, 459771c9cf30f378bdbd30fc65d17f7eb931bb59; fadae2953072e9005c5f1d64e1049edb043494dc up to, but not including, ae9d4caf6f133e884cf5fcda4982c493b35e5194; fadae2953072e9005c5f1d64e1049edb043494dc up to, but not including, 6c29a8ba084e89499ca77b947e07ae817f9c16ce; fadae2953072e9005c5f1d64e1049edb043494dc up to, but not including, 5f5b604e1e6bde4e889199168ee80fe8306d06ad; fadae2953072e9005c5f1d64e1049edb043494dc up to, but not including, ed5b030931292c94133437ac5e5ff580e498eabd; fadae2953072e9005c5f1d64e1049edb043494dc up to, but not including, 8d878059924f12c1bc24556a92ec56add74de3c8; and 1 more ranges | 84b3212b166b446faea27ebebb7161405ffceef9, 108963978a681c0c468d279cac2b930c27672877, 459771c9cf30f378bdbd30fc65d17f7eb931bb59, ae9d4caf6f133e884cf5fcda4982c493b35e5194, 6c29a8ba084e89499ca77b947e07ae817f9c16ce, 5f5b604e1e6bde4e889199168ee80fe8306d06ad |
| Linux | Linux Kernel | 4.19 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.94; 6.13 up to, but not including, 6.18.36; 6.19 up to, but not including, 7.0.13; 7.1 | 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
Official description
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(). Move the counter update before folio_put().
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/108963978a681c0c468d279cac2b930c27672877
- git.kernel.org/stable/c/459771c9cf30f378bdbd30fc65d17f7eb931bb59
- git.kernel.org/stable/c/5f5b604e1e6bde4e889199168ee80fe8306d06ad
- git.kernel.org/stable/c/6c29a8ba084e89499ca77b947e07ae817f9c16ce
- git.kernel.org/stable/c/84b3212b166b446faea27ebebb7161405ffceef9
- git.kernel.org/stable/c/8d878059924f12c1bc24556a92ec56add74de3c8
- git.kernel.org/stable/c/ae9d4caf6f133e884cf5fcda4982c493b35e5194
- git.kernel.org/stable/c/ed5b030931292c94133437ac5e5ff580e498eabd
Recent Use After Free vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.5 High severity
- 8.2 High severity
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