Linux: Use After Free
CVE-2026-98083 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.0 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 089d9c45ea49ffffe55a8fe08d0ce2536626e90a, b185bdf30313e213fa1c887fe22fc3d513c061d9, 2fbfd02bdfe12b20bd3cc7a3190fb32e3f7072f5 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 0.12% 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 089d9c45ea49ffffe55a8fe08d0ce2536626e90a or b185bdf30313e213fa1c887fe22fc3d513c061d9 or 2fbfd02bdfe12b20bd3cc7a3190fb32e3f7072f5 or b7b94923b3b5774d85a2a7c8d6eb9e3e0ef66685, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.158 or 6.12.111 or 6.18.53 or 7.2.7, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | ab69bf6f8970c09d3735c25094e9471d54365282 up to, but not including, 089d9c45ea49ffffe55a8fe08d0ce2536626e90a; 02c372e1f016e5113217597ab37b399c4e407477 up to, but not including, b185bdf30313e213fa1c887fe22fc3d513c061d9; 02c372e1f016e5113217597ab37b399c4e407477 up to, but not including, 2fbfd02bdfe12b20bd3cc7a3190fb32e3f7072f5; 02c372e1f016e5113217597ab37b399c4e407477 up to, but not including, b7b94923b3b5774d85a2a7c8d6eb9e3e0ef66685; 02c372e1f016e5113217597ab37b399c4e407477 up to, but not including, a8813a923f9e43f788b357fb55c35f7f6ed6f98c; 6.6.130 up to, but not including, 6.6.158; 6.7 | 089d9c45ea49ffffe55a8fe08d0ce2536626e90a, b185bdf30313e213fa1c887fe22fc3d513c061d9, 2fbfd02bdfe12b20bd3cc7a3190fb32e3f7072f5, b7b94923b3b5774d85a2a7c8d6eb9e3e0ef66685, a8813a923f9e43f788b357fb55c35f7f6ed6f98c, 6.6.158 |
| Linux | Linux Kernel | 6.6.130 up to, but not including, 6.6.158; 6.7 up to, but not including, 6.12.111; 6.13 up to, but not including, 6.18.53; 6.19 up to, but not including, 7.2.7; 7.3 | 6.6.158, 6.12.111, 6.18.53, 7.2.7 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/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: btrfs: fix transaction use-after-free in raid stripe insertion If allocation of a RAID stripe extent fails, btrfs_insert_one_raid_extent() aborts and ends the transaction before returning -ENOMEM. btrfs_finish_one_ordered(), the production caller through btrfs_insert_raid_extent(), still owns the transaction handle. It handles the error by aborting the transaction and then reaches the common exit path, which ends the transaction again. The premature end can free the handle and drop its transaction reference. Transaction cleanup can then free the transaction before the caller's second abort accesses the handle and transaction, resulting in use-after-free. Keep the abort at the failure site, but let the caller's common exit path end the transaction once, after it has finished using both objects.
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/089d9c45ea49ffffe55a8fe08d0ce2536626e90a
- git.kernel.org/stable/c/2fbfd02bdfe12b20bd3cc7a3190fb32e3f7072f5
- git.kernel.org/stable/c/a8813a923f9e43f788b357fb55c35f7f6ed6f98c
- git.kernel.org/stable/c/b185bdf30313e213fa1c887fe22fc3d513c061d9
- git.kernel.org/stable/c/b7b94923b3b5774d85a2a7c8d6eb9e3e0ef66685
Recent Use After Free vulnerabilities
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
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