Linux: Double Free
CVE-2026-64054 is a high-severity double 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 5098b223f0f0c5c18a3884a8b0ea5bd4a0c7bd75, 31767bf852b59f05125b58a17007e4cd1ea9eb2e, a9a2fa1da619f276580b0d4c5d12efac89e8642b 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 0.13% 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 5098b223f0f0c5c18a3884a8b0ea5bd4a0c7bd75 or 31767bf852b59f05125b58a17007e4cd1ea9eb2e or a9a2fa1da619f276580b0d4c5d12efac89e8642b, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.34 or 7.0.11, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 5d5d4700e75d861e83bf18eb6bf66ff90f85fe4e up to, but not including, 5098b223f0f0c5c18a3884a8b0ea5bd4a0c7bd75; 5d5d4700e75d861e83bf18eb6bf66ff90f85fe4e up to, but not including, 31767bf852b59f05125b58a17007e4cd1ea9eb2e; 5d5d4700e75d861e83bf18eb6bf66ff90f85fe4e up to, but not including, a9a2fa1da619f276580b0d4c5d12efac89e8642b; 6.13 | 5098b223f0f0c5c18a3884a8b0ea5bd4a0c7bd75, 31767bf852b59f05125b58a17007e4cd1ea9eb2e, a9a2fa1da619f276580b0d4c5d12efac89e8642b |
| Linux | Linux Kernel | 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.1 | 6.18.34, 7.0.11 |
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: net: shaper: reject duplicate leaves in GROUP request net_shaper_nl_group_doit() does not deduplicate NET_SHAPER_A_LEAVES entries. When userspace supplies the same leaf handle twice, the same old-parent pointer lands twice in old_nodes[]. The cleanup loop double frees the parent. Of course the same parent may still be in old_nodes[] twice if we are moving multiple of its leaves. Note that this patch also implicitly fixes the fact that the i >= leaves_count path forgets to set ret.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Double Free vulnerabilities
- 8.4 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 8.7 High severity
- 9.8 Critical severity
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