CVE-2026-64263
fuse-uring: fix moving cancelled entry to ent_in_userspace list
Description
In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix moving cancelled entry to ent_in_userspace list fuse_uring_cancel() moves entries that are available (these have no reqs attached) to the ent_in_userspace list. ent_list_request_expired() checks the first entry on ent_in_userspace and dereferences ent->fuse_req unconditionally, which will crash on a cancelled entry that was moved to this list. Fix this by freeing the entry and dropping queue_refs directly in fuse_uring_cancel(). This is safe because cancel is the cancel handler itself - after io_uring_cmd_done(), no more cancels will be dispatched for this command, and teardown serializes with cancel via queue->lock. Since cancel now decrements queue_refs, fuse_uring_abort() must no longer gate fuse_uring_abort_end_requests() on queue_refs > 0, as cancelled entries may have already dropped queue_refs while requests are still queued. Remove the gate so abort always flushes requests and stops queues.
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 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to the latest version.
- Apply the provided patch for fuse-uring.
- Ensure fuse_uring_cancel() frees entries correctly.
- Remove the queue_refs gate in fuse_uring_abort().
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-2026-64263.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64263 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-2026-64263
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-2026-64263 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64263 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': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': '50f3e03db823cabc41fe35c27d77c2bdb112baad', 'versionType': 'git'}, {'status': 'affected', 'version': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': 'e8afc85acdf329361b2d8df2ad9b52364686235f', 'versionType': 'git'}, {'status': 'affected', 'version': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': '198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev_uring.c', 'fs/fuse/dev_uring_i.h'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.16'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.16', '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', 'fs/fuse/dev_uring_i.h'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': '50f3e03db823cabc41fe35c27d77c2bdb112baad', 'versionType': 'git'}, {'status': 'affected', 'version': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': 'e8afc85acdf329361b2d8df2ad9b52364686235f', 'versionType': 'git'}, {'status': 'affected', 'version': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': '198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev_uring.c', 'fs/fuse/dev_uring_i.h'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.16'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.16', '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', 'fs/fuse/dev_uring_i.h'], 'defaultStatus': 'affected'}] -
Initial Analysis by [email protected]
Aug. 12, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NVD-CWE-noinfo 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) 6.16 up to (excluding) 6.18.39 Added Reference Type kernel.org: https://git.kernel.org/stable/c/198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/50f3e03db823cabc41fe35c27d77c2bdb112baad Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/e8afc85acdf329361b2d8df2ad9b52364686235f Types: Patch -
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': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': '50f3e03db823cabc41fe35c27d77c2bdb112baad', 'versionType': 'git'}, {'status': 'affected', 'version': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': 'e8afc85acdf329361b2d8df2ad9b52364686235f', 'versionType': 'git'}, {'status': 'affected', 'version': '4fea593e625cd50d4d11be227007849b12f17bfb', 'lessThan': '198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev_uring.c', 'fs/fuse/dev_uring_i.h'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.16'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.16', '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', 'fs/fuse/dev_uring_i.h'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix moving cancelled entry to ent_in_userspace list fuse_uring_cancel() moves entries that are available (these have no reqs attached) to the ent_in_userspace list. ent_list_request_expired() checks the first entry on ent_in_userspace and dereferences ent->fuse_req unconditionally, which will crash on a cancelled entry that was moved to this list. Fix this by freeing the entry and dropping queue_refs directly in fuse_uring_cancel(). This is safe because cancel is the cancel handler itself - after io_uring_cmd_done(), no more cancels will be dispatched for this command, and teardown serializes with cancel via queue->lock. Since cancel now decrements queue_refs, fuse_uring_abort() must no longer gate fuse_uring_abort_end_requests() on queue_refs > 0, as cancelled entries may have already dropped queue_refs while requests are still queued. Remove the gate so abort always flushes requests and stops queues. Added Reference https://git.kernel.org/stable/c/198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc Added Reference https://git.kernel.org/stable/c/50f3e03db823cabc41fe35c27d77c2bdb112baad Added Reference https://git.kernel.org/stable/c/e8afc85acdf329361b2d8df2ad9b52364686235f