Local crash via cancelled-entry null dereference
Published Jul 25, 2026 · Updated Jul 25, 2026
Denial of service in the Linux Kernel FUSE io_uring subsystem allows local users to crash the system by canceling an available entry. fuse_uring_cancel() moves an available entry with no attached request onto ent_in_userspace, where ent_list_request_expired() unconditionally dereferences the null ent->fuse_req pointer. Low-privileged local access and reachability of FUSE io_uring cancellation are required; successful exploitation causes a kernel crash without reported data disclosure or modification.
Summary
What happened
Denial of service in the Linux Kernel FUSE io_uring subsystem allows local users to crash the system by canceling an available entry. fuse_uring_cancel() moves an available entry with no attached request onto ent_in_userspace, where ent_list_request_expired() unconditionally dereferences the null ent->fuse_req pointer. Low-privileged local access and reachability of FUSE io_uring cancellation are required; successful exploitation causes a kernel crash without reported data disclosure or modification.
The record
- CVE
- CVE-2026-64263
- Published
- Jul 25, 2026
- Updated
- Jul 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 25, 2026CVE publishedPublication date reported by the CVE source.
- Jul 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4fea593e625cd50d4d11be227007849b12f17bfb <198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc
- Affected versionversion=4fea593e625cd50d4d11be227007849b12f17bfb <50f3e03db823cabc41fe35c27d77c2bdb112baad
- Affected versionversion=4fea593e625cd50d4d11be227007849b12f17bfb <e8afc85acdf329361b2d8df2ad9b52364686235f
- Affected versionversion=6.16
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo