Linux: Use After Free
CVE-2026-23158 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 815a8e3bf72811d402b30bd4a53cde5e9df7a563, 7bec90f605cfb138006f5ba575f2310593347110, 53ad4a948a4586359b841d607c08fb16c5503230 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 0.14% 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 815a8e3bf72811d402b30bd4a53cde5e9df7a563 or 7bec90f605cfb138006f5ba575f2310593347110 or 53ad4a948a4586359b841d607c08fb16c5503230, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.69 or 6.18.9, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 91581c4b3f29e2e22aeb1a62e842d529ca638b2d up to, but not including, 815a8e3bf72811d402b30bd4a53cde5e9df7a563; 91581c4b3f29e2e22aeb1a62e842d529ca638b2d up to, but not including, 7bec90f605cfb138006f5ba575f2310593347110; 91581c4b3f29e2e22aeb1a62e842d529ca638b2d up to, but not including, 53ad4a948a4586359b841d607c08fb16c5503230; 6.11 | 815a8e3bf72811d402b30bd4a53cde5e9df7a563, 7bec90f605cfb138006f5ba575f2310593347110, 53ad4a948a4586359b841d607c08fb16c5503230 |
| Linux | Linux Kernel | 6.11 up to, but not including, 6.12.69; 6.13 up to, but not including, 6.18.9; 6.19 | 6.12.69, 6.18.9 |
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 NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: gpio: virtuser: fix UAF in configfs release path The gpio-virtuser configfs release path uses guard(mutex) to protect the device structure. However, the device is freed before the guard cleanup runs, causing mutex_unlock() to operate on freed memory. Specifically, gpio_virtuser_device_config_group_release() destroys the mutex and frees the device while still inside the guard(mutex) scope. When the function returns, the guard cleanup invokes mutex_unlock(&dev->lock), resulting in a slab use-after-free. Limit the mutex lifetime by using a scoped_guard() only around the activation check, so that the lock is released before mutex_destroy() and kfree() are called.
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
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
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