Linux: Use After Free
CVE-2026-64259 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 e1711479e9068ea31b31353a702a51e639c3d059, a635f427d57e2012102ae4886b48d8955c59fb86, 1efd3d474fc0ba74dfd984249bca78807d739812 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 0.17% 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 e1711479e9068ea31b31353a702a51e639c3d059 or a635f427d57e2012102ae4886b48d8955c59fb86 or 1efd3d474fc0ba74dfd984249bca78807d739812, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.39 or 7.1.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | c090c8abae4b6b77a1bee116aa6c385456ebef96 up to, but not including, e1711479e9068ea31b31353a702a51e639c3d059; c090c8abae4b6b77a1bee116aa6c385456ebef96 up to, but not including, a635f427d57e2012102ae4886b48d8955c59fb86; c090c8abae4b6b77a1bee116aa6c385456ebef96 up to, but not including, 1efd3d474fc0ba74dfd984249bca78807d739812; 6.14 | e1711479e9068ea31b31353a702a51e639c3d059, a635f427d57e2012102ae4886b48d8955c59fb86, 1efd3d474fc0ba74dfd984249bca78807d739812 |
| Linux | Linux Kernel | 6.14 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.4 | 6.18.39, 7.1.4 |
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: fuse-uring: make a fuse_req on SQE commit only findable after memcpy Bad userspace might try to trick us and send commit SQEs request unique / commit-id of requests that are not even send to fuse-server (io_uring_cmd_done() not called) yet. fuse_uring_commit_fetch() ends the fuse request when the ring entry has a wrong state, but that could have caused a use-after-free with the memcpy operations in fuse_uring_send_in_task(). In order to avoid such races the call of fuse_uring_add_to_pq() is moved after the copy operations and just before completing the io-uring request - malicious userspace cannot find the request anymore until all prepration work in fuse-client/kernel is completed. This also moves fuse_uring_add_to_pq() a bit up in the code to avoid a forward declaration. Also not with a preparation commit, to make it easier to back port to older kernels.
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
- 9.8 Critical severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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