Linux: Use After Free
CVE-2026-31650 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 4b5251eebc2b1dedbb33fedf1b1109fea161b846, ea7468f61be033f4e18b95f2912010ed1d175d75, ef0448c569b37ceabdd038e9faa311e5179127b0 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 0.15% 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 4b5251eebc2b1dedbb33fedf1b1109fea161b846 or ea7468f61be033f4e18b95f2912010ed1d175d75 or ef0448c569b37ceabdd038e9faa311e5179127b0 or 8f4d20a710225ec7a565f6a0459862d3b1f32330, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.23 or 6.19.13, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 117a9c589ce0cf68065c007a02fd94da01e1181a up to, but not including, 4b5251eebc2b1dedbb33fedf1b1109fea161b846; dcfdd698dc521c6046e9b80c16281575efb25d23 up to, but not including, ea7468f61be033f4e18b95f2912010ed1d175d75; dcfdd698dc521c6046e9b80c16281575efb25d23 up to, but not including, ef0448c569b37ceabdd038e9faa311e5179127b0; dcfdd698dc521c6046e9b80c16281575efb25d23 up to, but not including, 8f4d20a710225ec7a565f6a0459862d3b1f32330; 6.17 | 4b5251eebc2b1dedbb33fedf1b1109fea161b846, ea7468f61be033f4e18b95f2912010ed1d175d75, ef0448c569b37ceabdd038e9faa311e5179127b0, 8f4d20a710225ec7a565f6a0459862d3b1f32330 |
| Linux | Linux Kernel | 6.17.1 up to, but not including, 6.18.23; 6.19 up to, but not including, 6.19.13; 6.17; 7.0 | 6.18.23, 6.19.13 |
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: mmc: vub300: fix use-after-free on disconnect The vub300 driver maintains an explicit reference count for the controller and its driver data and the last reference can in theory be dropped after the driver has been unbound. This specifically means that the controller allocation must not be device managed as that can lead to use-after-free. Note that the lifetime is currently also incorrectly tied the parent USB device rather than interface, which can lead to memory leaks if the driver is unbound without its device being physically disconnected (e.g. on probe deferral). Fix both issues by reverting to non-managed allocation of the controller.
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
Other references
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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