CVE-2026-64259 Details
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.
A use-after-free vulnerability has been identified in the Linux kernel's fuse-uring implementation. This issue arises because userspace can send commit requests for unique identifiers that have not yet been processed by the fuse server. The problem is exacerbated by the fuse_uring_commit_fetch() function, which prematurely ends the fuse request when it encounters an incorrect state, potentially leading to a use-after-free condition during memory copy operations. To mitigate this, the sequence of operations has been adjusted: the fuse_uring_add_to_pq() function is now called after the necessary data has been copied, ensuring that malicious userspace cannot access the request until all preparations are complete. This vulnerability affects several versions of the Linux kernel.
Users can upgrade to the latest stable version of the Linux kernel, where this vulnerability has been addressed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/1efd3d474fc0ba74dfd984249bca78807d739812 | kernel.org | Patch |
| https://git.kernel.org/stable/c/a635f427d57e2012102ae4886b48d8955c59fb86 | kernel.org | Patch |
| https://git.kernel.org/stable/c/e1711479e9068ea31b31353a702a51e639c3d059 | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-416 | Use After Free | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 6.14, < 6.18.39 >= 6.19, < 7.1.4 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 17, 2026 | CVE Modified | kernel.org |
| Aug 12, 2026 | Initial Analysis | [email protected] |
| Jul 27, 2026 | CVE Modified | kernel.org |
| Jul 25, 2026 | New CVE Received | kernel.org |