Linux: Double Free
CVE-2026-43328 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 56bc91ee78babe9578585a2bc137abc4b3115ff3, 4b9118e93d2499bb2808ef3742fa0ce06f4f8117, 019ea28629720c220daedf38107c8787f330dc05 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 56bc91ee78babe9578585a2bc137abc4b3115ff3 or 4b9118e93d2499bb2808ef3742fa0ce06f4f8117 or 019ea28629720c220daedf38107c8787f330dc05 or da39ee627fd82b52068d4d5f115749a8b7d271f9, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 6.1.168 or 6.6.134 or 6.12.81, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 4ebe36c94aed95de71a8ce6a6762226d31c938ee up to, but not including, 56bc91ee78babe9578585a2bc137abc4b3115ff3; 4ebe36c94aed95de71a8ce6a6762226d31c938ee up to, but not including, 4b9118e93d2499bb2808ef3742fa0ce06f4f8117; 4ebe36c94aed95de71a8ce6a6762226d31c938ee up to, but not including, 019ea28629720c220daedf38107c8787f330dc05; 4ebe36c94aed95de71a8ce6a6762226d31c938ee up to, but not including, da39ee627fd82b52068d4d5f115749a8b7d271f9; 4ebe36c94aed95de71a8ce6a6762226d31c938ee up to, but not including, 427d048e4f6acbfa01b5a8062449fe0ee8987c0d; 4ebe36c94aed95de71a8ce6a6762226d31c938ee up to, but not including, d2703b4f8fb7cc6f0dfdb2dc2359cc46189e7357; 4ebe36c94aed95de71a8ce6a6762226d31c938ee up to, but not including, 3bf9d023d2329a0e5379f2fd09d06ef09729cd9d; 4ebe36c94aed95de71a8ce6a6762226d31c938ee up to, but not including, 6dcf9d0064ce2f3e3dfe5755f98b93abe6a98e1e; and 3 more ranges | 56bc91ee78babe9578585a2bc137abc4b3115ff3, 4b9118e93d2499bb2808ef3742fa0ce06f4f8117, 019ea28629720c220daedf38107c8787f330dc05, da39ee627fd82b52068d4d5f115749a8b7d271f9, 427d048e4f6acbfa01b5a8062449fe0ee8987c0d, d2703b4f8fb7cc6f0dfdb2dc2359cc46189e7357 |
| Linux | Linux Kernel | 5.2 up to, but not including, 5.10.253; 5.11 up to, but not including, 6.1.168; 6.2 up to, but not including, 6.6.134; 6.7 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; 5.1.6; 7.0 | 5.10.253, 6.1.168, 6.6.134, 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 NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: cpufreq: governor: fix double free in cpufreq_dbs_governor_init() error path When kobject_init_and_add() fails, cpufreq_dbs_governor_init() calls kobject_put(&dbs_data->attr_set.kobj). The kobject release callback cpufreq_dbs_data_release() calls gov->exit(dbs_data) and kfree(dbs_data), but the current error path then calls gov->exit(dbs_data) and kfree(dbs_data) again, causing a double free. Keep the direct kfree(dbs_data) for the gov->init() failure path, but after kobject_init_and_add() has been called, let kobject_put() handle the cleanup through cpufreq_dbs_data_release().
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
- git.kernel.org/stable/c/019ea28629720c220daedf38107c8787f330dc05
- git.kernel.org/stable/c/3bf9d023d2329a0e5379f2fd09d06ef09729cd9d
- git.kernel.org/stable/c/427d048e4f6acbfa01b5a8062449fe0ee8987c0d
- git.kernel.org/stable/c/56bc91ee78babe9578585a2bc137abc4b3115ff3
- git.kernel.org/stable/c/6dcf9d0064ce2f3e3dfe5755f98b93abe6a98e1e
- git.kernel.org/stable/c/d2703b4f8fb7cc6f0dfdb2dc2359cc46189e7357
- git.kernel.org/stable/c/da39ee627fd82b52068d4d5f115749a8b7d271f9
Other references
Recent Double Free vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
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