What is CVE-2021-47124?

CVE-2021-47124 is a high-severity vulnerability in Linux. CVSS score: 7.8/10. Published 2024-03-15.

How severe is CVE-2021-47124?

High severity. CVSS v3 base score is 7.8 out of 10.

Is CVE-2021-47124 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Linux

CVE-2021-47124

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix link timeout refs WARNING: CPU: 0 PID: 10242 at lib/refcount.c:28 refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28 RIP: 0010:refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28 Call Trace: __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] io_put_req fs/io_uring.c:2140 [inline] io_queue_linked_timeout fs/io_uring.c:6300 [inline] __io_queue_sqe+0xbef/0xec0 fs/io_uring.c:6354 io_submit_sqe fs/io_uring.c:6534 [inline] io_submit_sqes+0x2bbd/0x7c50 fs/io_uring.c:6660 __do_sys_io_uring_enter fs/io_uring.c:9240 [inline] __se_sys_io_uring_enter+0x256/0x1d60 fs/io_uring.c:9182 io_link_timeout_fn() should put only one reference of the linked timeout request, however in case of racing with the master request's completion first io_req_complete() puts one and then io_put_req_deferred() is called.

Published 2024-03-15 · last modified 2026-08-04.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (14.7th percentile), scored 2026-10-23.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 14.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Linux — versions 5.12, 567c81912cec641db75ac6cb64c63f8367c97d19, 5.11.6
Linux Kernel — versions 5.13

Public proof-of-concept exploits

NaInSec/CVE-LIST

References

416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)

Frequently asked questions

What is CVE-2021-47124?: CVE-2021-47124 is a high-severity vulnerability in Linux. CVSS score: 7.8/10. Published 2024-03-15.
How severe is CVE-2021-47124?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2021-47124 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.