Local denial of service via exiting-task cancellation
Published May 24, 2024 · Updated May 11, 2026
Improper io_uring cancellation in Linux 5.15 through 5.15.5 allows local users to cause availability loss during task exit. The io_req_task_link_timeout() callback invokes io_try_cancel_userdata() from fallback work after the request task begins exiting, although cancellation requires the original task context. A low-privileged local user must arrange linked-timeout fallback during task teardown, producing a kernel warning and availability loss.
Summary
What happened
Improper io_uring cancellation in Linux 5.15 through 5.15.5 allows local users to cause availability loss during task exit. The io_req_task_link_timeout() callback invokes io_try_cancel_userdata() from fallback work after the request task begins exiting, although cancellation requires the original task context. A low-privileged local user must arrange linked-timeout fallback during task teardown, producing a kernel warning and availability loss.
The record
- CVE
- CVE-2021-47569
- Published
- May 24, 2024
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 24, 2024CVE publishedPublication date reported by the CVE source.
- May 11, 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=5.15
- Affected versionversion=89b263f6d56e683ddcf7643140271ef6e36c72b9 <3d2a1e68fd9904fdc1b02f2e7d40ca47df7ba39f
- Affected versionversion=89b263f6d56e683ddcf7643140271ef6e36c72b9 <617a89484debcd4e7999796d693cf0b77d2519de
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