Linux: Use After Free
CVE-2026-43447 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 1b034f2429ce6b45ce74dc266175d277acafc5c4, 90cc8b2add29b57288025b51c70bc647e7cccb12, efc54fb13d79117a825fef17364315a58682c7ec 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 1b034f2429ce6b45ce74dc266175d277acafc5c4 or 90cc8b2add29b57288025b51c70bc647e7cccb12 or efc54fb13d79117a825fef17364315a58682c7ec, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.19 or 6.19.9, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 7c01dbfc8a1c5f8b8e4a7907ab06db1449d478d0 up to, but not including, 1b034f2429ce6b45ce74dc266175d277acafc5c4; 7c01dbfc8a1c5f8b8e4a7907ab06db1449d478d0 up to, but not including, 90cc8b2add29b57288025b51c70bc647e7cccb12; 7c01dbfc8a1c5f8b8e4a7907ab06db1449d478d0 up to, but not including, efc54fb13d79117a825fef17364315a58682c7ec; 6.15 | 1b034f2429ce6b45ce74dc266175d277acafc5c4, 90cc8b2add29b57288025b51c70bc647e7cccb12, efc54fb13d79117a825fef17364315a58682c7ec |
| Linux | Linux Kernel | 6.15 up to, but not including, 6.18.19; 6.19 up to, but not including, 6.19.9; 7.0 | 6.18.19, 6.19.9 |
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: iavf: fix PTP use-after-free during reset Commit 7c01dbfc8a1c5f ("iavf: periodically cache PHC time") introduced a worker to cache PHC time, but failed to stop it during reset or disable. This creates a race condition where `iavf_reset_task()` or `iavf_disable_vf()` free adapter resources (AQ) while the worker is still running. If the worker triggers `iavf_queue_ptp_cmd()` during teardown, it accesses freed memory/locks, leading to a crash. Fix this by calling `iavf_ptp_release()` before tearing down the adapter. This ensures `ptp_clock_unregister()` synchronously cancels the worker and cleans up the chardev before the backing resources are destroyed.
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
Recent Use After Free vulnerabilities
- 7.3 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.