CVE-2026-64259
fuse-uring: make a fuse_req on SQE commit only findable after memcpy
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.
INFO
Published Date :
July 25, 2026, 10:17 a.m.
Last Modified :
Aug. 17, 2026, 5:17 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to the latest version.
- Ensure fuse-uring module is properly configured.
- Review code for similar race conditions.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64259.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64259 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64259
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64259 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64259 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': 'e1711479e9068ea31b31353a702a51e639c3d059', 'versionType': 'git'}, {'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': 'a635f427d57e2012102ae4886b48d8955c59fb86', 'versionType': 'git'}, {'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': '1efd3d474fc0ba74dfd984249bca78807d739812', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev_uring.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fuse/dev_uring.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': 'e1711479e9068ea31b31353a702a51e639c3d059', 'versionType': 'git'}, {'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': 'a635f427d57e2012102ae4886b48d8955c59fb86', 'versionType': 'git'}, {'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': '1efd3d474fc0ba74dfd984249bca78807d739812', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev_uring.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fuse/dev_uring.c'], 'defaultStatus': 'affected'}] -
Initial Analysis by [email protected]
Aug. 12, 2026
Action Type Old Value New Value Added CWE CWE-416 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.1.4 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.14 up to (excluding) 6.18.39 Added Reference Type kernel.org: https://git.kernel.org/stable/c/1efd3d474fc0ba74dfd984249bca78807d739812 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/a635f427d57e2012102ae4886b48d8955c59fb86 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/e1711479e9068ea31b31353a702a51e639c3d059 Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 27, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 25, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': 'e1711479e9068ea31b31353a702a51e639c3d059', 'versionType': 'git'}, {'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': 'a635f427d57e2012102ae4886b48d8955c59fb86', 'versionType': 'git'}, {'status': 'affected', 'version': 'c090c8abae4b6b77a1bee116aa6c385456ebef96', 'lessThan': '1efd3d474fc0ba74dfd984249bca78807d739812', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev_uring.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fuse/dev_uring.c'], 'defaultStatus': 'affected'}] Added 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. Added Reference https://git.kernel.org/stable/c/1efd3d474fc0ba74dfd984249bca78807d739812 Added Reference https://git.kernel.org/stable/c/a635f427d57e2012102ae4886b48d8955c59fb86 Added Reference https://git.kernel.org/stable/c/e1711479e9068ea31b31353a702a51e639c3d059