Linux: Use After Free
CVE-2026-43019 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 7502c1cf303b69f71d085f5ff7251b0e1b0f09df, 66d432e9b45bae7881ffcdb12cd8fd0bf254ef02, 7d568fede8eac91161a60b710aa920abe9b0fb9f 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 0.1% 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 7502c1cf303b69f71d085f5ff7251b0e1b0f09df or 66d432e9b45bae7881ffcdb12cd8fd0bf254ef02 or 7d568fede8eac91161a60b710aa920abe9b0fb9f or bad65b4b0a96139f023eadc28a33125963208449, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.81 or 6.18.22 or 6.19.12, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a091289218202bc09d9b9caa8afcde1018584aec up to, but not including, 7502c1cf303b69f71d085f5ff7251b0e1b0f09df; a091289218202bc09d9b9caa8afcde1018584aec up to, but not including, 66d432e9b45bae7881ffcdb12cd8fd0bf254ef02; a091289218202bc09d9b9caa8afcde1018584aec up to, but not including, 7d568fede8eac91161a60b710aa920abe9b0fb9f; a091289218202bc09d9b9caa8afcde1018584aec up to, but not including, bad65b4b0a96139f023eadc28a33125963208449; a091289218202bc09d9b9caa8afcde1018584aec up to, but not including, a2639a7f0f5bf7d73f337f8f077c19415c62ed2c; 3a273cd0f47dd672d37736e623849374f9ab9ce9; d8570c4c3f2a3e51b3c8b5e6ec898364c5c03062; 6.4.16 up to, but not including, 6.5; and 2 more ranges | 7502c1cf303b69f71d085f5ff7251b0e1b0f09df, 66d432e9b45bae7881ffcdb12cd8fd0bf254ef02, 7d568fede8eac91161a60b710aa920abe9b0fb9f, bad65b4b0a96139f023eadc28a33125963208449, a2639a7f0f5bf7d73f337f8f077c19415c62ed2c, 6.5 |
| Linux | Linux Kernel | 6.6 up to, but not including, 6.12.81; 6.13 up to, but not including, 6.18.22; 6.19 up to, but not including, 6.19.12; 6.4.16; 6.5.3; 7.0 | 6.12.81, 6.18.22, 6.19.12 |
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: Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync hci_conn lookup and field access must be covered by hdev lock in set_cig_params_sync, otherwise it's possible it is freed concurrently. Take hdev lock to prevent hci_conn from being deleted or modified concurrently. Just RCU lock is not suitable here, as we also want to avoid "tearing" in the configuration.
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
Other references
Recent Use After Free vulnerabilities
- 8.1 High severity
- 8.1 High severity
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
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