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CVE-2021-47461

15
FAUCET Score

CVE-2021-47461 addresses a race condition in the Linux kernel's userfaultfd mechanism, specifically between writeprotect operations and the exit_mmap() function during process termination. This vulnerability, affecting Linux kernel versions, could lead to a denial of service (A:H) due to the race condition. Rated as Medium severity (CVSS 4.7), it requires low privileges (PR:L) and high attack complexity (AC:H), with no direct impact on confidentiality or integrity. There is no evidence of active exploitation, public exploit code, or significant community discussion, suggesting a low immediate threat.

Impacted Technologies

VendorProductVersion(s)CPE
>= 5.7, < 5.10.76CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 5.11, < 5.14.15CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
5.15CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
5.15CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
5.15CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.7MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
1.0
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.16%
Probability of exploitation in next 30 days
EPSS Percentile
6.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0016 is in the 34th percentile among its peer group of 1,297 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

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

Remediation

Patch Available

Vendor Patches (6)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt-0:4.18.0-553.16.1.rt7.357.el8_10
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-0:4.18.0-553.16.1.el8_10
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportFixed in: kernel-0:4.18.0-372.121.1.el8_6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Telecommunications Update ServiceFixed in: kernel-0:4.18.0-372.121.1.el8_6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Update Services for SAP SolutionsFixed in: kernel-0:4.18.0-372.121.1.el8_6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.8 Extended Update SupportFixed in: kernel-0:4.18.0-477.81.1.el8_8
View patch

Vendor Advisories (1)

redhatCVE-2021-47461Moderate

kernel: userfaultfd: fix a race between writeprotect and exit_mmap()

May 22, 2024

References

git.kernel.org / stable/c/149958ecd0627a9f1e9c678c25c665400054cd6a
Patch
git.kernel.org / stable/c/3cda4bfffd4f755645577aaa9e96a606657b4525
Patch
git.kernel.org / stable/c/cb185d5f1ebf900f4ae3bf84cee212e6dd035aca
Patch