Linux: Use After Free
CVE-2026-64099 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 acd55ea40d03e06f20a9986363019e0e5173990e, 0f8efc45740b0628a787d1b0be8a0ddabd700625, 69c2a1fec2e7ca25598180816f3bc56e1842eb41 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 acd55ea40d03e06f20a9986363019e0e5173990e or 0f8efc45740b0628a787d1b0be8a0ddabd700625 or 69c2a1fec2e7ca25598180816f3bc56e1842eb41 or b0fe80c0b9250b35e2211bf3117e7aca814a21b0, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.93 or 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 | 9ba0ff3e083f6a4a0b6698f06bfff74805fefa5f up to, but not including, acd55ea40d03e06f20a9986363019e0e5173990e; 9ba0ff3e083f6a4a0b6698f06bfff74805fefa5f up to, but not including, 0f8efc45740b0628a787d1b0be8a0ddabd700625; 9ba0ff3e083f6a4a0b6698f06bfff74805fefa5f up to, but not including, 69c2a1fec2e7ca25598180816f3bc56e1842eb41; 9ba0ff3e083f6a4a0b6698f06bfff74805fefa5f up to, but not including, b0fe80c0b9250b35e2211bf3117e7aca814a21b0; 6.8 | acd55ea40d03e06f20a9986363019e0e5173990e, 0f8efc45740b0628a787d1b0be8a0ddabd700625, 69c2a1fec2e7ca25598180816f3bc56e1842eb41, b0fe80c0b9250b35e2211bf3117e7aca814a21b0 |
| Linux | Linux Kernel | 6.8 up to, but not including, 6.12.93; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.1 | 6.12.93, 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 CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: drm/v3d: Fix use-after-free of CPU job query arrays on error path The CPU job ioctl's fail label calls kvfree() on cpu_job's timestamp and performance query arrays after v3d_job_cleanup(), which drops the job's last reference and frees cpu_job. Reading cpu_job at that point is a use-after-free. Also, on the early v3d_job_init() failure path, it is a NULL dereference, since v3d_job_deallocate() zeroes the local pointer. In the success path, the arrays are released from the scheduler's .free_job callback, but on the error path, they are freed manually, as the job was never pushed to the scheduler. While the success path deals with this correctly, the fail path doesn't. On top of that, the manual kvfree() calls only free the array storage; they don't drm_syncobj_put() the per-query syncobjs that v3d_timestamp_query_info_free() and v3d_performance_query_info_free() release on the success path. So the same fail path that triggers the use-after-free also leaks one syncobj reference per query. Unify the CPU job teardown into the CPU job's kref destructor, mirroring v3d_render_job_free(). The scheduler's .free_job slot reverts to the generic v3d_sched_job_free() and the fail label drops the manual kvfree() calls, leaving a single teardown path that is reached from both the scheduler and the ioctl error path. That removes the use-after-free, the NULL dereference, and the syncobj leak by construction.
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
Recent Use After Free vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
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