Linux: Use After Free
CVE-2026-64562 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 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 b82c3144d8264265448292ca406f60bafeba3b6f, 4f50e6aec16f69627dbad5704d1e90a255d766a7, dc3eecfa219ebc9d01eaf7d1abd1441efe884dab 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 0.16% 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 b82c3144d8264265448292ca406f60bafeba3b6f or 4f50e6aec16f69627dbad5704d1e90a255d766a7 or dc3eecfa219ebc9d01eaf7d1abd1441efe884dab or af56298e9d86e6098cd1d2e155cb2949b7c45412, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.265 or 5.15.216 or 6.1.183 or 6.6.148, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 up to, but not including, b82c3144d8264265448292ca406f60bafeba3b6f; 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 up to, but not including, 4f50e6aec16f69627dbad5704d1e90a255d766a7; 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 up to, but not including, dc3eecfa219ebc9d01eaf7d1abd1441efe884dab; 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 up to, but not including, af56298e9d86e6098cd1d2e155cb2949b7c45412; 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 up to, but not including, 589419470030a89f16cf19300658b6dc644ca946; 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 up to, but not including, 8001d2ce9d9bd09118ce523aef595aa094573ae3; 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 up to, but not including, 1dabef6e206568bf9d9ade74f6e56a48ea35695d; 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 up to, but not including, 622ebfac01ba4f9c0060cebd41257fe46fc4a0b3; and 1 more ranges | b82c3144d8264265448292ca406f60bafeba3b6f, 4f50e6aec16f69627dbad5704d1e90a255d766a7, dc3eecfa219ebc9d01eaf7d1abd1441efe884dab, af56298e9d86e6098cd1d2e155cb2949b7c45412, 589419470030a89f16cf19300658b6dc644ca946, 8001d2ce9d9bd09118ce523aef595aa094573ae3 |
| Linux | Linux Kernel | 4.9.1 up to, but not including, 5.10.265; 5.11 up to, but not including, 5.15.216; 5.16 up to, but not including, 6.1.183; 6.2 up to, but not including, 6.6.148; 6.7 up to, but not including, 6.12.101; 6.13 up to, but not including, 6.18.42; 6.19 up to, but not including, 7.1.6; 4.9; and 1 more ranges | 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42 |
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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:C/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: KVM: nVMX: Hide shadow VMCS right after VMCLEAR free_nested() frees the shadow VMCS while vmcs01 still points to it. But because it is asynchronous with respect to loaded_vmcs_clear(), the vCPU might migrate before the pointer is cleared and __loaded_vmcs_clear() may then execute VMCLEAR. The VMCS needs to stay attached until its explicit VMCLEAR completes, but then it can be hidden and the page safely freed.
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
- git.kernel.org/stable/c/1dabef6e206568bf9d9ade74f6e56a48ea35695d
- git.kernel.org/stable/c/4f50e6aec16f69627dbad5704d1e90a255d766a7
- git.kernel.org/stable/c/589419470030a89f16cf19300658b6dc644ca946
- git.kernel.org/stable/c/622ebfac01ba4f9c0060cebd41257fe46fc4a0b3
- git.kernel.org/stable/c/8001d2ce9d9bd09118ce523aef595aa094573ae3
- git.kernel.org/stable/c/af56298e9d86e6098cd1d2e155cb2949b7c45412
- git.kernel.org/stable/c/b82c3144d8264265448292ca406f60bafeba3b6f
- git.kernel.org/stable/c/dc3eecfa219ebc9d01eaf7d1abd1441efe884dab
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
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