CVE-2021-47569

io_uring: fail cancellation for EXITING tasks

MEDIUM
5.5
CVSS Score
Published: May 24, 2024 at 03:12 PM UTC
Updated: June 17, 2026 at 04:17 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring: fail cancellation for EXITING tasks WARNING: CPU: 1 PID: 20 at fs/io_uring.c:6269 io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269 CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.16.0-rc1-syzkaller #0 Workqueue: events io_fallback_req_func RIP: 0010:io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269 Call Trace: <TASK> io_req_task_link_timeout+0x6b/0x1e0 fs/io_uring.c:6886 io_fallback_req_func+0xf9/0x1ae fs/io_uring.c:1334 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> We need original task's context to do cancellations, so if it's dying and the callback is executed in a fallback mode, fail the cancellation attempt.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.15 ≤ v < 5.15.65.15 ≤ v < 5.165.155.16 rc15.16 rc289b263f6d56e683ddcf7643140271ef6e36c72b9
Vendor states this is fixed in 3d2a1e68fd9904fdc1b02f2e7d40ca47df7ba39f (fixed)
Vendor states this is fixed in 617a89484debcd4e7999796d693cf0b77d2519de (fixed)
Vendor states this is fixed in 5.15 (unaffected)
Vendor states this is fixed in 5.15.6 (unaffected)
Vendor states this is fixed in 5.16 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/3d2a1e68fd9904fdc1b02f2e7d40ca47df7ba39f
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/617a89484debcd4e7999796d693cf0b77d2519de

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
NVD-CWE-noinfo

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