CVE-2021-4083

24

FAUCET Score

CVE-2021-4083 is a read-after-free vulnerability in the Linux kernel's Unix domain socket garbage collection, affecting versions prior to 5.16-rc4, including Debian, NetApp, and Oracle distributions. This flaw, rated HIGH (CVSS 7.0), can be triggered by a local user exploiting a race condition during simultaneous close() and fget() calls, potentially leading to system crashes or privilege escalation. While the vulnerability has a high potential impact, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

Vendor	Product	Version(s)	CPE
		< 4.4.294CPE matchmatch criteria	cpe:2.3:o:linux:linux_kernel::::::::
		>= 4.5, < 4.9.292CPE matchmatch criteria	cpe:2.3:o:linux:linux_kernel::::::::
		>= 4.10, < 4.14.257CPE matchmatch criteria	cpe:2.3:o:linux:linux_kernel::::::::
		>= 4.15, < 4.19.220CPE matchmatch criteria	cpe:2.3:o:linux:linux_kernel::::::::
		>= 4.20, < 5.4.164CPE matchmatch criteria	cpe:2.3:o:linux:linux_kernel::::::::

CVSS Data

CVSS version used by this source: 3.1

7.0HIGH

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

Exploitability Score

1.0

Impact Score

5.9

CvssVersion

3.1

Exploit Intelligence

EPSS Score

0.31%

Probability of exploitation in next 30 days

EPSS Percentile

23.3%

Percentile rank of EPSS score among Peer Group

As of 2026-07-28

Model: v2026.06.15

This CVE's current EPSS score of 0.0031 is in the 59th percentile among its peer group of 1,525 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.4 InfoSec Media, 0.1 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (29)

microsoftpatch availablevia msrc

Product: 18907-16820Fixed in: 5.10.93.1-2

microsoftpatch availablevia msrc

Product: cm1 kernel 5.10.93.1-2 on CBL Mariner 1.0Fixed in: 5.10.93.1-2

oraclepatch availablevia nvd_reference

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7Fixed in: kernel-0:3.10.0-1160.62.1.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.3 Advanced Update SupportFixed in: kernel-0:3.10.0-514.101.1.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.4 Advanced Update SupportFixed in: kernel-0:3.10.0-693.99.1.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.6 Advanced Update Support(Disable again in 2026 - SPRHEL-7118)Fixed in: kernel-0:3.10.0-957.92.1.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.6 Telco Extended Update SupportFixed in: kernel-0:3.10.0-957.92.1.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.6 Update Services for SAP SolutionsFixed in: kpatch-patch

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.6 Update Services for SAP SolutionsFixed in: kernel-0:3.10.0-957.92.1.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.7 Advanced Update SupportFixed in: kernel-0:3.10.0-1062.66.1.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.7 Telco Extended Update SupportFixed in: kernel-0:3.10.0-1062.66.1.el7

redhatpatch availablevia nvd_reference

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.7 Update Services for SAP SolutionsFixed in: kpatch-patch

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt-0:4.18.0-372.9.1.rt7.166.el8

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8Fixed in: kernel-0:4.18.0-372.9.1.el8

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8.1 Update Services for SAP SolutionsFixed in: kernel-0:4.18.0-147.64.1.el8_1

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8.1 Update Services for SAP SolutionsFixed in: kpatch-patch

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: kernel-rt-0:4.18.0-193.79.1.rt13.129.el8_2

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: kernel-0:4.18.0-193.79.1.el8_2

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: kpatch-patch

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8.4 Extended Update SupportFixed in: kernel-rt-0:4.18.0-305.45.1.rt7.117.el8_4

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8.4 Extended Update SupportFixed in: kpatch-patch

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 8.4 Extended Update SupportFixed in: kernel-0:4.18.0-305.45.1.el8_4

redhatpatch availablevia redhat_api

Product: Red Hat Virtualization 4 for Red Hat Enterprise Linux 7Fixed in: redhat-virtualization-host-0:4.3.22-20220330.1.el7_9

redhatpatch availablevia redhat_api

Product: Red Hat Virtualization 4 for Red Hat Enterprise Linux 8Fixed in: redhat-virtualization-host-0:4.5.0-202205291010_8.6

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7.7 Update Services for SAP SolutionsFixed in: kernel-0:3.10.0-1062.66.1.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7Fixed in: kernel-rt-0:3.10.0-1160.62.1.rt56.1203.el7

redhatpatch availablevia redhat_api

Product: Red Hat Enterprise Linux 7Fixed in: kpatch-patch

Vendor Advisories (2)

microsoft2022-Jan/CVE-2021-4083Important

A read-after-free memory flaw was found in the Linux kernel's garbage collection for Unix domain socket file handlers in the way users call close() and fget() simultaneously and can potentially trigger a race condition. This flaw allows a local user to crash the system or escalate their privileges on the system. This flaw affects Linux kernel versions prior to 5.16-rc4.

redhatCVE-2021-4083Important

kernel: fget: check that the fd still exists after getting a ref to it

References

bugzilla.redhat.com / show_bug.cgi

Issue TrackingPatchThird Party Advisory

git.kernel.org / pub/scm/linux/kernel/git/torvalds/linux.git/commit

Mailing ListPatch

lists.debian.org / debian-lts-announce/2022/03/msg00011.html

Mailing ListThird Party Advisory

lists.debian.org / debian-lts-announce/2022/03/msg00012.html

Mailing ListThird Party Advisory

security.netapp.com / advisory/ntap-20220217-0005

Third Party Advisory

debian.org / security/2022/dsa-5096

Third Party Advisory

oracle.com / security-alerts/cpujul2022.html

PatchThird Party Advisory