Linux: Double Free
CVE-2026-43007 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 2dd67966f39a2abf8ccb4865031c722e40e01b7f, 08021f2d4a557d6491e3bcc288e96425f50aa3cf, f403094d9075d7c565a3d81002b781c325cb3c07 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 2dd67966f39a2abf8ccb4865031c722e40e01b7f or 08021f2d4a557d6491e3bcc288e96425f50aa3cf or f403094d9075d7c565a3d81002b781c325cb3c07 or ee0180e77e6c8482644569632065411de844c515, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.134 or 6.12.81 or 6.18.22 or 6.19.12, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 129776ac2e38231fa9c02ce20e116c99de291666 up to, but not including, 2dd67966f39a2abf8ccb4865031c722e40e01b7f; 129776ac2e38231fa9c02ce20e116c99de291666 up to, but not including, 08021f2d4a557d6491e3bcc288e96425f50aa3cf; 129776ac2e38231fa9c02ce20e116c99de291666 up to, but not including, f403094d9075d7c565a3d81002b781c325cb3c07; 129776ac2e38231fa9c02ce20e116c99de291666 up to, but not including, ee0180e77e6c8482644569632065411de844c515; 129776ac2e38231fa9c02ce20e116c99de291666 up to, but not including, 2feec5ae5df785658924ab6bd91280dc3926507c; 6.4 | 2dd67966f39a2abf8ccb4865031c722e40e01b7f, 08021f2d4a557d6491e3bcc288e96425f50aa3cf, f403094d9075d7c565a3d81002b781c325cb3c07, ee0180e77e6c8482644569632065411de844c515, 2feec5ae5df785658924ab6bd91280dc3926507c |
| Linux | Linux Kernel | 6.4 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; 7.0 | 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: accel/qaic: Handle DBC deactivation if the owner went away When a DBC is released, the device sends a QAIC_TRANS_DEACTIVATE_FROM_DEV transaction to the host over the QAIC_CONTROL MHI channel. QAIC handles this by calling decode_deactivate() to release the resources allocated for that DBC. Since that handling is done in the qaic_manage_ioctl() context, if the user goes away before receiving and handling the deactivation, the host will be out-of-sync with the DBCs available for use, and the DBC resources will not be freed unless the device is removed. If another user loads and requests to activate a network, then the device assigns the same DBC to that network, QAIC will "indefinitely" wait for dbc->in_use = false, leading the user process to hang. As a solution to this, handle QAIC_TRANS_DEACTIVATE_FROM_DEV transactions that are received after the user has gone away.
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/08021f2d4a557d6491e3bcc288e96425f50aa3cf
- git.kernel.org/stable/c/2dd67966f39a2abf8ccb4865031c722e40e01b7f
- git.kernel.org/stable/c/2feec5ae5df785658924ab6bd91280dc3926507c
- git.kernel.org/stable/c/ee0180e77e6c8482644569632065411de844c515
- git.kernel.org/stable/c/f403094d9075d7c565a3d81002b781c325cb3c07
Recent Double 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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